Implantable electrode assemblies, including implantable electrode assemblies for the brain, and associated systems, devices, and methods

Abstract

Implantable electrode assemblies, including implantable electrode assemblies for the brain, and associated systems, devices and methods are disclosed herein. In one embodiment, an electrode shank comprises (i) a plurality of electrodes and (ii) a body extending between a proximal end region and a distal end region opposite the proximal end region. The body can include a plurality of non-conductive layers arranged in a stack. The body can further include a plurality of conductive traces formed on each of the plurality of non-conductive layers. The plurality of electrodes can be disposed on the body, and each of the plurality of conductive traces can extend from the proximal end region to a corresponding one of the plurality of electrodes.

Description

IMPLANTABLE ELECTRODE ASSEMBLIES, INCLUDING IMPLANTABLE ELECTRODE ASSEMBLIES FOR THE BRAIN, AND ASSOCIATED SYSTEMS, DEVICES, AND METHODSCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 578,718, filed August 25, 2023, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure generally relates to implantable devices. For example, several embodiments of the present technology are directed to implantable devices for interfacing with neural tissue (e.g., to stimulate the tissue and treat one or more neural disorders, diseases, and / or conditions, such as vision loss) and other living tissue.BACKGROUND

[0003] Several common disorders of the brain, spinal cord, and peripheral nervous system arise due to abnormal electrical activity in biological (neural) circuits. Such neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across neuronal membranes that, in turn, can initiate neuronal action potentials, which are the means of information transfer in the nervous system. Based on this mechanism, it is possible to input sensory information into the central nervous system by coding the sensory information as a sequence of electrical pulses, which are relayed to the central nervous system via the prosthetic device. In this way, it is possible to provide artificial sensations, such as vision.

[0004] For example, recording and / or stimulating the nervous system can include the use of deep brain stimulation (DBS) electrodes and / or shanks, which may be configured to stimulate brain regions with millimetric and sub-millimetric precision. Existing methods, however, are limited in that they are only able to record from a small volume of tissue, or a small population of neurons. Additionally, the placement of such electrodes is highly invasive and results in damage or destruction of normal brain tissue, including neurons. Accordingly, the number of electrodes that can be safely placed is limited, as is the ability to adj ust the spatial placement of the electrodes once they are placed (with the exception of minor adjustments of the electrodes atthe time of placement). In practice, DBS techniques have an excellent safety profile demonstrated over two decades of standard clinical use, but as these electrodes are macroscopic, only a small number (typically one or two) are placed in any single patient.

[0005] Accordingly, the invasiveness of delivery procedures for a small number of electrodes in conventional systems has limited the applications of neural recording and stimulation. As such, it would be advantageous to have minimally invasive delivery devices and systems for delivering high-bandwidth neural interfaces to a target site of a subject for neural recording and stimulation.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure. The drawings should not be taken to limit the disclosure to the specific embodiments depicted, but are for explanation and understanding only.

[0007] FIG. 1A illustrates a cross-section (coronal view) of a human brain including a lateral geniculate nucleus (LGN) region.

[0008] FIGS. IB and 1C illustrate enlarged views of the LGN region of FIG. 1A, with FIG. 1C illustrating corresponding layers of the LGN region.

[0009] FIGS. 2A and 2B are partially schematic side and rear views, respectively, of a prosthetic system configured in accordance with various embodiments of the present technology.

[0010] FIGS. 3A-3E are partially schematic views of an electrode shank configured in accordance with various embodiments of the present technology.

[0011] FIGS. 4A-4C are partially schematic views of another electrode shank configured in accordance with various embodiments of the present technology.

[0012] FIG. 5 is a partially schematic perspective view of an electrode shank interfacing with a stylet, each configured in accordance with various embodiments of the present technology.

[0013] FIGS. 6A-6C are partially schematic perspective views of an electrode array group arrangement configured in accordance with various embodiments of the present technology._0_

[0014] FIGS. 7A and 7B are partially schematic front and back perspective views, respectively, of a grid insert configured in accordance with various embodiments of the present technology.

[0015] FIG. 8 is a partially schematic perspective view of another grid insert configured in accordance with various embodiments of the present technology.

[0016] FIG. 9 is a partially schematic perspective view of a bushing configured in accordance with various embodiments of the present technology.

[0017] FIG. 10 is a partially schematic perspective view of a microdrive system configured in accordance with various embodiments of the present technology.

[0018] FIG. 11 is a partially schematic diagram illustrating an optimized electrode group layout corresponding to a grid insert configured in accordance with various embodiments of the present technology.

[0019] FIGS. 12A and 12B illustrate an example brain LGN with an electrode array inserted therein in accordance with various embodiments of the present technology.

[0020] FIG. 13 illustrates a flowchart illustrating a method for inserting an electrode array at a target site in an organ or other tissue in accordance with various embodiments of the present technology.

[0021] FIG. 14 illustrates a partially schematic top view and a partially schematic bottom view of a desired trajectory for inserting electrodes into a brain in accordance with various embodiments of the present technology.

[0022] FIGS. 15A-15E illustrate various steps of the method of FIG. 13.

[0023] FIG. 16 illustrates a schematic representation of example hardware included in various components of systems configured in accordance with various embodiments of the present technology.

[0024] FIGS. 17A-17C are partially schematic diagrams illustrating steps for fabricating an electrode shank in accordance with various embodiments of the present technology.

[0025] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to aid in understanding of various aspects of the present technology. In addition, common but well-understood elements or methods that are useful or necessary in a commercially feasible embodiment are often not depicted in the figures, or described in detail below, to avoid unnecessarily obscuring the description of various aspects of the present technology.DETAILED DESCRIPTION

[0026] Disclosed herein are high-bandwidth neural interfaces (and associated systems, devices, and methods) for the brain that allow for improved spatial resolution, temporal resolution, reduced collateral damage to the normal brain tissue and optimization for electrical recording and / or electrical stimulation. Embodiments may include biocompatible, implantable devices that can be implanted into the brain to form a brain-computer interface. The high- bandwidth neural interfaces (hereinafter referred to as “electrodes”) may be used for recording and / or stimulation, including for example, for applying light, current, voltage, or drugs.

[0027] In the following description, specific details are set forth to provide a thorough understanding of aspects of the present technology. One skilled in the relevant art will recognize, however, that the systems, devices, and techniques described herein can be practiced without one or more of the specific details set forth herein, or with other methods, components, materials, etc. For example, the following disclosure describes the use of electrodes with respect to a visual prosthesis. The present technology, however, is not so limited. Indeed, the implantable electrodes of this disclosure may additionally, or alternatively, be used for other neural recording and / or stimulation purposes, such as therapeutics (e.g., for treatment of Parkinson’s), olfactory prosthesis, or the like.

[0028] As another example, while several embodiments of the present technology described herein relate to an electrode array and methods for implanting the electrode array in LGN neural tissue, the present technology is not so limited. Indeed, the present technology can be employed in other situations in which tissue or nerve cells can be stimulated to rehabilitate, activate, or restore functionality of an organ, appendage, or part of a human, animal, etc. For example, an electrode array of the present technology can be used to modulate the activity of other laminar neural tissue structures.

[0029] As still another example, while several embodiments of the present technology described herein generally relate to cranial access systems and methods, systems and methods of the present technology may additionally, or alternatively, be used in relation to other bone through which it is desirable to pass a catheter or other similar device, such as, but not limitedto, spinal vertebrae, hip, or the like. As a specific example, systems and methods of the present technology may be used for access to a vertebral body of a spinal vertebra.

[0030] As yet another example, while the devices and techniques disclosed herein are described with respect to a human body or subject, it is understood that the devices and techniques be applied to a non-human body or subject (e.g., in veterinary medicine).

[0031] Reference throughout this specification to an “example” or an “embodiment” means that a particular feature, structure, or characteristic described in connection with the example or embodiment is included in at least one example or embodiment of the present technology. Thus, use of the phrases “for example,” “as an example,” “in one embodiment,” or “an embodiment” herein are not necessarily all referring to the same example or embodiment and are not necessarily limited to the specific example or embodiment discussed. Furthermore, features, structures, or characteristics of the present technology described herein may be combined in any suitable manner to provide further examples or embodiments of the present technology.

[0032] Spatially relative terms (e.g., “beneath,” “below,” “over,” “under,” “above,” “upper,” “top,” “bottom,” “left,” “right,” “center,” “middle,” and the like) may be used herein for ease of description to describe one element’s or feature’s relationship relative to one or more other elements or features, as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of a device or system in use or operation, in addition to the orientation depicted in the figures. For example, if a device or system illustrated in the figures is rotated, turned, or flipped about a horizontal axis, elements or features described as “below” or “beneath” or “under” one or more other elements or features may then be oriented “above” the one or more other elements or features. Thus, the terms “below” and “under” are non-limiting and can encompass both an orientation of above and below. The device or system may additionally, or alternatively, be otherwise oriented (e.g., rotated ninety degrees about a vertical axis, or at other orientations) than illustrated in the figures, and the spatially relative descriptors used herein are interpreted accordingly. In addition, it will also be understood that when an element is referred to as being “between” two other elements, it can be the only element between the two other elements, or one or more intervening elements may also be present.

[0033] It should also be noted that the terms “proximal” and “distal” as used herein, are intended to refer to a direction toward (proximal) and away from (distal) a surgeon or other user.Furthermore, the term electrical signal, as used herein, may include, for example, electrical impulses and signals with time-varying degrees of voltage, current, frequency, pulse duration, and / or wavelength.A. Overview

[0034] Many leading causes of blindness are currently incurable — and once the damage is done, patients with vision loss from diabetic retinopathy, glaucoma, or trauma to the eyes or optic nerve currently have no hope of recovering vision. Treatment options for most types of age-related macular degeneration (AMD), the leading cause of vision loss in older Americans, are limited. Anti-vascular endothelial growth factor (anti-VEGF) drugs may help slow or stop disease progression of wet AMD, and in some cases reverse some vision loss. But patients with severe vision loss from AMD are often without hope of any vision recovery.

[0035] The lateral geniculate nucleus (LGN), which is also sometimes referred to as the lateral geniculate body (LGB), is a compact subcortical structure in the thalamus critical for vision. More specifically, the LGN processes information from retinal ganglion cells in the retina and transmits information to neurons in the visual cortex. The LGN is organized into six main layers, having retinotopic organization (linear mapping of visual space), with the fovea over- represented. Within the layers of the LGN, neurons receiving input from retinal ganglion cells have small discrete receptive files characterized by on-center or off-center center-surround organization. FIG. 1A illustrates a cross-section of a human brain 100 including an LGN region 101. FIGS. IB and 1C illustrate enlarged views of the LGN region 101 of FIG. 1A, with FIG. 1C illustrating corresponding layers of the LGN region 101. (Four of the six layers of the LGN region 101 are labeled as layer I, layer II, layer III, and layer VI, respectively, in FIG. 1C.)

[0036] As discussed above, it is possible to input sensory information into the central nervous system by coding the sensory information as a sequence of electrical pulses which are relayed to the central nervous system via a prosthetic device that includes implantable electrodes. In this way, it is possible to provide artificial sensations, including vision. The retinotopy, the over-presentation of the fovea, and the small discrete receptive files of neurons within the layers of an LGN make the LGN an ideal target for a visual prothesis. For example, the retinotopy and foveal over-presentation allow for straightforward mapping of visual space to stimulation space, and the small receptive fields mean that each stimulation site can be treated as a uniquely addressable pixel.

[0037] An LGN visual prosthesis can cause electrical stimulation within the human thalamus (e.g., the LGN) and evoke the perception of points of light (phosphenes) at specific regions in space. Due to mechanical and electrical limitations in LGN prosthetic devices, resulting phosphenes are typically not contiguous with other phosphenes, have a round shape, and are either light or dark (e.g., white or black), and have color and dynamics related to the receptive fields of the particular local neurons that were stimulated to produce a given phosphene. This sparse array of light percepts (referred to as a phosphene pattern) provides a unique visual information modality, akin to a pointillist painting or a braille display. The phosphene density (akin to pixel resolution of a display) and dynamic scene exploration are the two main drivers of visual prosthesis learning and performance.

[0038] Designing a prosthetic device that can stimulate the LGN in a controllable and perceptible manner, however, has proven challenging because of the morphology and location of the LGN within the brain. The LGN is a stratified compact structure that is located deep within the brain (in the thalamus) and that receives input from the retina via the optic nerve and relays information to the primary visual cortex. One of the main challenges in the field, therefore, has been the development of electrodes that can selectively activate specific neurons or neuronal pathways. As such, electrodes must be designed to not only reach the deeply seated LGN but also to provide a plurality of electrode contacts within the 3D structure of the LGN. Moreover, since the LGN is located after the optic chiasm, a bilateral implant is required to cover both visual hemifields. In addition, while prosthetic devices that include electrode arrays allow for access of hundreds or more unique stimulation sites, electrode arrays necessarily cause insult to surrounding tissue when such an electrode array is implanted.

[0039] The present technology is directed to prosthetic devices (and associated systems and methods) that include electrode arrays that are implantable in living tissue and that address several of the challenges discussed above. For example, several embodiments described in detail below are directed (a) to systems with electrodes for stimulating the LGN (e.g., to restore vision) or other parts of the central nervous system, and (b) to methods of implanting the electrodes in living tissue.

[0040] In one embodiment, a prosthetic device includes an electrode array for neural recording and stimulation (e.g., within an LGN region of a brain). The electrode array includes multiple electrode shanks that are not necessarily spatially confined with respect to each other (e.g., are not attached to a common substrate at proximal ends of the electrode shanks). Multipleelectrodes are positioned / disposed in or on each electrode shank. A set of electrodes can be arranged along a length of each shank, and / or on one or both sides / faces of each shank. Furthermore, all or a subset of the electrodes can be independently electrically addressable. As such, the electrode array is configured to provide a high density of electrodes in a three- dimensional configuration.

[0041] Including multiple electrodes on each electrode shank can provide several advantages. For example, this approach enables multiple monopolar, locally bi-polar, or more generally multipolar (multisite) stimulation, permitting arbitrary shaping of the generated electric field. This approach enables flexibility of selecting a channel close to a target stimulation site, even when placement of an electrode is not accurate. Multiple electrode sites per shank also enable simultaneous recording and stimulation of a volume of tissue. For stimulation, a larger composite site (formed of multiple electrodes) also increases the effective site area to allow increased charge injection while maintaining safe electrochemical and biological limits. This also allows, for example, precise current steering to selectively stimulate neural structures.

[0042] In another embodiment, a prosthetic device includes an electrode array including a plurality of electrode shanks. Each electrode shank can include a body extending between a proximal end and a distal end, a plurality of planar non-conductive layers included within the body, and a plurality of conductive traces formed on each of the plurality of planar non- conductive layers. Each of the plurality of conductive traces can extend from the proximal end and terminate at a contact formed in or on an upper surface or a lower surface of the body. The body can include a plurality of contact pairs that are used to apply bipolar stimulation. A contact pair can comprise a first contact on the upper surface of the shank and a second contact on the lower surface of the shank. Optionally, one or more of the electrode shanks can include a hole formed within a tip section at the distal end of the shanks. A stylet or rod can be threaded or inserted through the hole and affixed the body of the shank (e.g., via dissolvable polyethylene glycol (PEG) or another suitable material).

[0043] In still another embodiment, a visual prosthetic device includes a controller and an electrode array comprising a plurality of electrode shanks. Each shank can include a body extending between a proximal end and a distal end, a plurality of planar non-conductive layers included within the body, and a plurality of conductive traces formed on each of the plurality of planar non-conductive layers. Each of the conductive traces can extend from the proximal end and terminate at an electrode formed in or on an upper surface or a lower surface of the body.The electrodes can be arranged in a plurality of pairs (e.g., to apply bipolar stimulation). A pair of electrodes can comprise a first contact on the upper surface of shank body and a second contact on the lower surface of the shank body. In a specific example, the shank may include 50 or 64 electrodes arranged in 25 or 32 pairs, respectively.

[0044] The electrode array can be used to electrophysiologically localize and stimulate targets (e.g., within wide regions deep within a brain). For example, each electrode shank can be configured for insertion within an LGN region of a subject’s brain. Optionally, the plurality of electrode pairs can be configured to simulate neurons within the LGN region and / or record signals from neurons within the LGN region. For example, the plurality of electrode pairs can be configured to evoke a desired phosphene pattern within space. In some embodiments, the controller can be configured to cause the plurality of electrodes to stimulate neurons within the LGN region to evoke a phosphene pattern.

[0045] In some embodiments, the electrode array can be a first electrode array, and the visual prosthetic device can include a second electrode array comprising a second plurality of electrode shanks, each of the plurality of electrode shanks comprising a body and corresponding electrodes configured for insertion within another LGN region of the subject’s brain.

[0046] The electrode arrays of the present technology can be deployed within living tissue using minimally invasive techniques. Indeed, the present disclosure describes systems and methods for insertion of the electrode array within a subject’s brain, such as along a desired trajectory and / or using a personalized grid insert. In one embodiment, a method for simultaneous insertion of a plurality of electrodes of an electrode array within a brain includes inserting a bushing (or cranial bolt) within the brain along a first trajectory; determining an actual trajectory of the cranial bushing using a fiducial marker; determining, based on the first trajectory and the actual trajectory, properties of one or more channels in a grid insert; forming the grid insert using the determined properties; and inserting, via the one or more channel in the grid insert, the plurality of the electrodes within the brain. The first trajectory can be configured for insertion of the plurality of electrodes (a) within an LGN region of the brain and / or (b) along a pathway that extends through the parietal-occipital junction of the brain and avoids injuring optic radiations (e.g., white-matter projections — geniculocortical and corticogeniculate fibers — connecting the LGN to the visual cortex).B. Selected Embodiments of Implantable Electrode Assemblies and Associated Systems, Devices, and MethodsProsthetic System

[0047] FIGS. 2A and 2B are partially schematic side and rear views, respectively, of a prosthetic system 210 configured in accordance with various embodiments of the present technology. In the illustrated embodiment, the prosthetic system 210 is a visual prosthesis usable to stimulate an LGN region 101 of a human brain 100 and thereby evoke percepts of light (herein referred to as “phosphenes”) to provide an artificial sensation of vision. As discussed above, however, prosthetic systems of the present technology can be used to stimulate other neural or living tissue (in a human or non-human subject), including to treat one or more other disorders, diseases, and / or conditions besides vision loss.

[0048] As shown, the prosthetic system 210 (“the system 210”) includes wearable glasses 212, a first pulse generator 216a, a first electrode array 220a operably coupled to the first pulse generator 216a via a first set of flexible cables 217, a second pulse generator 216b, and a second electrode array 220b operably coupled to the second pulse generator 216b via a second set of flexible cables 217. As discussed in greater detail below, the first and second electrode arrays 220a and 220b can be inserted into a subject’s brain 100 and positioned about or within an LGN region 101 of the brain 100. For example, the first electrode array 220a (a) can be inserted into a subject’s brain 100 via a first bushing 218a that is situated in a corresponding burr hole in the subject’s head (specifically, in the skull, full thickness), and (b) can be positioned such that electrodes of the first electrode array 220a are located about or within a left LGN region 101 of the brain 100. Additionally, or alternatively, the second electrode array 220b (a) can be inserted into a subject’s brain 100 via a second bushing 218b that is situated in a corresponding burr hole in the subject’s head, and (b) can be positioned such that electrodes of the second electrode array 220b are located about or within a right LGN region 101 of the brain 100.

[0049] In some embodiments, the first pulse generator 216a and / or the second pulse generator 216b can be positioned, fully implanted, internal to the subject’s scalp and external to the skull. In other embodiments, the first pulse generator 216a and / or the second pulse generator 216b can be at least partially implantable within the subject (e.g., within the subject’s head, such as beneath the subject’s scalp, internal the subject’s skull, or implanted within the subject’s brain 100). As discussed in greater detail below, the first pulse generator 216a can be configured to control electrodes of the first electrode array 220a to stimulate target tissue of the left LGNregion 101, and the second pulse generator 216b can be configured to control electrodes of the second electrode array 220b to stimulate target tissue of the right LGN region 101. In at least some of these embodiments, the first and second pulse generators 216a and 216b can be used to control the first and second electrode arrays 220a and 220b, respectively, to provide bilateral retinotopic LGN stimulation. Thus, the first and second pulse generators 216a and 216b can collectively be referred to herein as a “bilateral pulse generator.”

[0050] As shown in FIG. 2A, the wearable glasses 212 can include a first image sensor 213a and a second image sensor 213b. In some embodiments, the first image sensor 213a can be part of a first digital camera and / or correspond to the first electrode array 220a. In these and other embodiments, the second image sensor 213b can be part of a second digital camera and / or correspond to the second electrode array 220b. The first image sensor 213a and the second image sensor 213b can be usable to capture images of an external scene.

[0051] As best shown in FIG. 2B, the wearable glasses 212 can further include a first embedded computer 214a, a second embedded computer 214b, a first telemetry device 215a corresponding to the first embedded computer 214a, and a second telemetry device 215b corresponding to the second embedded computer 214b. The first embedded computer 214a and / or the second embedded computer 214b can be a controller or processor. The first embedded computer 214a can be configured to (a) process images captured using the first image sensor 213a, and (b) generate stimulation patterns corresponding to the images. Similarly, the second embedded computer 214b can be configured to (a) process images captured using the second image sensor 213b, and (b) generate stimulation patterns corresponding to the images. The first and second telemetry devices 215a and 215b can be transmitters (e.g., wired or wireless transmitters, such as wireless, near- field communication transmitters) configured to transmit stimulation patterns generated by the first and second embedded computers 214a and 214b, respectively, to the first and second pulse generators 216a and 216b, respectively.

[0052] In operation, the prosthetic system 210 captures images of an external scene using the first and second image sensors 213a and 213b. In turn, the first and second embedded computers 214a and 214b (or one or more paired portable / wearable computational devices that are discretely placed and tethered for communication via digital cables or wireless communication) process images captured by the first and second image sensors 213a and 213b, respectively, and generate stimulation patterns corresponding to the acquired images. Stimulation patterns generated by the first embedded computer 214a are transmitted to the firstpulse generator 216a by the first telemetry device 215a, and stimulation patterns generated by the second embedded computer 214b are transmitted to the second pulse generator 216b by the second telemetry device 215b. Thereafter, the first and second pulse generators 216a and 216b control electrodes of the first and second electrode arrays 220a and 220b, respectively, to deliver the stimulation patterns to the left LGN region 101 and the right LGN region 101, respectively, of the brain 100. The stimulation patterns evoke phosphenes that simulate the images acquired by the first and second images sensors 213a and 213b. In this manner, the system 210 is usable to deliver bilateral retinotopic LGN stimulation and thereby provide a subject an artificial sensation of vision.

[0053] Although shown in FIGS. 2A and 2B with two image sensors 213, two embedded computers 214, two telemetry devices 215, two pulse generators 216, two electrode arrays 220, two sets of cables 217, and two bushings 218, prosthetic systems configured in accordance with other embodiments of the present technology can include any number (e.g., only one, two, more than two) of any one or more of these components. As a specific example, a prosthetic system configured in accordance with various embodiments of the present technology can include a single image sensor, a single embedded computer, a single telemetry device, a single pulse generator, a single electrode array, a single set of cables, and a single bushing. As another specific example, prosthetic systems configured in accordance with various embodiments of the present technology can each include one or two image sensors, one or two embedded computers, one or two pulse generators, one or two telemetry devices, one or two electrode arrays, one or two sets of cables, and / or one or two bushings.Electrode Array

[0054] A detailed description of electrode arrays configured in accordance with various embodiments of the present technology is now provided. Electrode arrays (e.g., the electrode arrays 220a and 220b of FIGS. 2A and 2B) of the present technology are each described in detail below as including a plurality of electrode shanks (also referred to herein as “shanks’"), with each shank including a plurality of electrodes (also referred to herein as “contacts,” “active sites,” or “conductors”). The shanks can be arranged in electrode array groupings (e.g., of five or another number of electrode shanks), and each electrode array can include one or more electrode array groupings (e.g., eight or another number of electrode array groupings).

[0055] All or a subset of the individual electrodes on a shank can be used for recording and / or stimulation (e.g., bipolar, monopolar, near-monopolar, unipolar, and / or near-unipolarstimulation). In these and other embodiments, the plurality of electrodes on a shank can be arranged in pairs, with each pair including an electrode fashioned as a source electrode and another electrode fashioned as a sink electrode. Each pair of electrodes can be configured to apply bipolar stimulation to surrounding / target tissue and therefore may be referred to herein as a “bipolar electrode” or as a “single-shank bipolar electrode.” The single-shank bipolar electrodes can allow for charge injection into surrounding / target tissue that is tightly confined between the pair of electrodes of the shank. When an electrode of a single shank is used to apply monopolar / unipolar or near-monopolar / near-unipolar stimulation, the electrode may be referred to herein as a “monopolar / unipolar electrode’7“single-shank monopolar / unipolar electrode” or as a “near-monopolar / near-unipolar electrode / “single-shank near-monopolar / near-unipolar electrode,” respectively.

[0056] Additionally, or alternatively, the plurality of shanks can be arranged in pairs, with each pair including a shank having at least one electrode fashioned as a source electrode and another shank having at least one electrode fashioned as a sink electrode. Depending on a distance separating the source and sink electrodes, the source and sink electrodes on the shanks of a pair can be configured to apply (a) bipolar stimulation to surrounding / target tissue (when the source and sink electrodes are relatively close to one another) and / or (b) monopolar / unipolar or near-monopolar / near-unipolar stimulation to surrounding / target tissue (when the source and sink electrodes are relatively further apart from one another). When used to apply monopolar / unipolar or near-monopolar / near-unipolar stimulation, the source and sink electrodes of a pair of shanks may be referred to herein as a “monopolar / unipolar electrode” / “multi-shank monopolar / unipolar electrode” or as a “near-monopolar / near-unipolar electrode / “multi-shank near-monopolar / near-unipolar electrode,” respectively. When used to apply bipolar stimulation, the source and sink electrodes of a pair of shanks may be referred to herein as a “bipolar electrode” or as a “multi-shank bipolar electrode.” The multi-shank bipolar electrodes can allow for charge injection into surrounding / target tissue that is confined between each pair of electrodes.

[0057] FIGS. 3A-3E are partially schematic views of an electrode shank 330 configured in accordance with various embodiments of the present technology. More specifically, FIGS. 3 A and 3B are partially schematic top planar and bottom planar views, respectively, of the electrode shank 330; FIG. 3C is a partially schematic side view of the electrode shank 330 with a partially schematic, detailed, cross-sectional view of a portion of the electrode shank 330 also shown; FIG. 3D is a partially schematic perspective view of a distal end region 341 of the electrodeshank 330; and FIG. 3E is a partially schematic, cross-sectional view of a portion of the electrode shank 330 taken along line 3E-3E of FIG. 3D.

[0058] Referring to FIGS. 3A and 3B, the electrode shank 330 (“the shank 330”) includes a distal end region 341 and a proximal end region 342 opposite the distal end region 341. The shank 330 further includes a width W. Comparing FIGS. 3A and 3B with FIG. 3C, the width W of the shank 330 is greater than its height H. Thus, the partial cross-sectional view of the shank 330 in FIG. 3E illustrates that the shank 330 includes a generally rectangular cross-sectional shape. In other embodiments, the width W and height H of the shank 330 can be substantially equal such that the cross-sectional shape of shank 330 is generally square. In some embodiments, the width W and the height H of the shank 330 each range from about 500 nanometers to about 100 microns, about 40 microns to about 250 microns, such as about 50 microns to about 200 microns, about 100 microns to about 150 microns, or the like. The shank 330 can have a length ranging from about 1 cm to about 10 cm, such as about 2 cm to about 8 cm, about 3 cm to about 6 cm, or the like.

[0059] The shank 330 includes a body 331. In some embodiments, the body 331 of the shank 330 has a layered (or “stacked”) configuration. For example, the body 331 can include multiple layers (or “sheets”) of non-conductive thin film with elongated electrical connections (also referred to herein as “traces”) disposed therebetween. For purposes of this application, it is understood that a “thin film” (and “thin-film” as an adjective) is defined as a layer of material of thickness ranging from fractions of a nanometer to tens of microns, including up to about 150 microns, such as 130 microns or less, 120 microns or less, 110 microns or less, 100 microns or less, or the like.

[0060] In the specific example illustrated in FIGS. 3C-3E, the body 331 of the shank 330 includes four layers of non-conductive thin film (identified individually in FIGS. 3C-3E as a first layer 332a, a second layer 332b, a third layer 332c, and a fourth layer 332d). As best shown in FIG. 3E, a plurality of traces 333 are disposed on each of the non-conductive thin film layers 332a-332d. More specifically, a first plurality of traces 333A is disposed on the first layer 332a of non-conductive thin fdm, a second plurality of traces 333B is disposed on the second layer 332b of non-conductive thin film, a third plurality of traces 333C is disposed on the third layer 332c of non-conductive thin film, and a fourth plurality of traces 333D is disposed on the fourth layer 332d of non-conductive thin film. In some embodiments, the traces 333A-333D are thin- film conductive electrical components, such as thin-film conductive electrical components thatcan be positioned on one of the layers 332a-332d via a photolithography or photoengraving process, as described in further detail below.

[0061] The shank 330 of FIGS. 3A-3E further includes two non-conductive thin film cover layers 332e and 332f. In the illustrated embodiment, the non-conductive thin film cover layers 332e and 332f are separate layers from one another and from the layers 332a-332d of the body 331. In some embodiments, the non-conductive thin film cover layers 332e and / or 332f can extend along the sides of the body 331 of the shank 330, such as to form an enclosed shank configuration encapsulating the non-conductive thin film layers 332a-332d. In at least some of these embodiments, the non-conductive thin film cover layers 332e and 332f can be integral with one another and form a unitary cover layer (e.g., that extends fully about a circumference of the body 331). Optionally, the cover layers 332e and / or 332f can be contiguous with the body 331 (e.g., with one or more of the layers 332a-332d), and not separately formed. The cover layers 332e, 332f and / or the layers 332a-332d can be made from, for example, SU-8 photoresist, polyimide, mylar, silicon, or another suitable dielectric material / film. In some embodiments, one or more of the non-conductive layers 332a-33f-2f have a thickness ranging from about 0.0002 mm to about 0.127 mm, such as about 0.00254 mm to about 0.0127 mm, about 0.0127 mm to about 0.0254 mm, or the like.

[0062] In some embodiments, the shank 330 incorporates thin-film conductive materials disposed in or on one of more of the ultra-thin dielectric materials / layers, thereby resulting in multiple conductors (e.g., electrodes, contacts, active sites, etc.) in high density. In embodiments in which thin-film conductive materials are disposed in a thin-film dielectric layer, the thin-film conductive materials can be at least partially embedded within the thin-film dielectric layer and / or exposed at or through an outward-facing surface of the thin-film dielectric layer. It is understood that thin-film conductors, as contemplated herein, can be formed by a variety of processes, including spraying, spin-coating, dip-coating, chemical vapor deposition (CVD), evaporation, and / or sputtering, as described in greater detail below.

[0063] In the embodiment illustrated in FIGS. 3A-3E, the shank 330 includes a first plurality of thin-film conductors 334 (hereinafter referred to as “electrodes 334”) disposed in or on the non-conductive cover layer 332e, and a second plurality of thin-film conductors 335 (hereinafter referred to as “electrodes 335”) disposed in or on the cover layer 332f. The electrodes 334, 335 are formed of a conductive material, such as copper, nickel, gold, titanium, platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, or the like.

[0064] Traces 333 disposed on one of the layers 332a-332d can be electrically isolated from one another, and / or can extend from the proximal end region 342 of the shank 330 to one of the electrodes 334, 335 at the distal end region 341 of the shank 330. For example, referring to FIG. 3C, each trace 333 can have an elongated section 333a that extends from the proximal end region 342 of the shank 330 toward the distal end region 341 of the shank 330 along the length of a corresponding one of the non-conductive layers 332a-332e. Each of the traces 333 can further include a transverse (or “side”) extension 333b that extends from a distal end of the corresponding elongated section 333a to a corresponding one of the electrodes 334 disposed in or on the cover layer 332e or to a corresponding one of the electrodes 335 disposed in or on the cover layer 332f. In some embodiments, each side extension 333b is a separate electrical connection that is electrically coupled to the corresponding elongated section 333a of a trace 333. Alternatively, the side extension 333b can be integral with the corresponding elongated section 333a of the trace 333 such that the trace 333 is a single, unitary component.

[0065] In the specific example shown in FIG. 3C, a side extension 333b- 1 of a first trace 333 couples a first electrode 334a to an elongated section 333a- 1 of the first trace 333 that extends along the length of the layer 332b. Similarly, a side extension 333b-2 of a second trace 333 couples a second electrode 334b to an elongated section 333a-2 of the second trace 333 that extends along the length of the layer 332b, and a side extension 333b-3 of a third trace 333 couples a third electrode 334c to an elongated section 333a-3 of the third trace 333 that extends along the length of the layer 332b. The shank 330 includes similar traces 333 that are each electrically coupled to one of the electrodes 335 and that each include elongated sections that extend along the length of one of the layers 332a-332d (e.g., the layer 332c shown in FIG. 3C). As a result, each trace 333 can be electrically coupled to a different one of the electrodes 334, 335, and can be configured to electrically couple that one of the electrodes 334, 335 to the proximal end region 342 of the shank 330.

[0066] A proximal end of each trace 333 can be coupled to a proximal connector. In one implementation, the proximal connector (not shown) is a known connector such as an IC socket, a flat flexible connector, a ball grid array, or any other known connector allowing for the shank 330 and all or a subset of the traces 333 therein to be electrically coupled to an external controller (not shown) via the proximal connector (not shown). As a result, each of the electrodes 334, 335 can be individually addressable by the external controller via the proximal connector and a corresponding one of the traces. As discussed above, individual ones and / or groups of theelectrodes 334, 335 can be used for sensing (or recording), for stimulation, or for any other known purpose of a neural electrode.

[0067] The electrodes 334, 335 of a shank 330 can be arranged in pairs. For example, an electrode 334 disposed in or on the cover layer 332e can be paired with a corresponding electrode 335 disposed in or on the cover layer 332f. Continuing with this example, the electrode 334 and the electrode 335 of the pair can be configured to apply bipolar stimulation to surrounding / target tissue. As such, the electrode 334 and the electrode 335 can be referred to collectively as a “bipolar electrode” or as a “bipolar unit.” As another example, an electrode 334 disposed in or on the cover layer 332e can be paired with another electrode 334 disposed in or on the cover layer 332e to form a bipolar electrode, and / or an electrode 335 disposed in or on the cover layer 332f can be paired with another electrode 335 disposed in or on the cover layer 332f to form a bipolar electrode. In some embodiments, bipolar electrodes of a shank 330 can be independently addressable and / or addressable in groups, such as to deliver bipolar stimulation to surrounding / target tissue.

[0068] The number of independently addressable bipolar electrodes on a shank 330 can vary and can be limited only by deposition resolution, shank surface area, electrode uses, and / or other practical considerations. In some embodiments, the number of bipolar electrodes on a shank 330 can range from about 20 to about 50, such as about 30 to about 40, about 30, about 31, about 32, about 33, about 34, about 35, about 36, or the like. As a specific example, each of the thin film layers 332a and 332b can include 16 traces electrically coupling 16 electrodes 334 disposed in or on the cover layer 332e to the proximal end region 342 of the shank 330, and each of the thin film layers 332c and 332d can include 16 traces electrically coupling electrodes 335 disposed in or on the cover layer 332f to the proximal end region 342 of the shank 330. In this specific example, the shank 330 can therefore include 32 electrodes 334 and 32 electrodes 335. Continuing with this specific example, the electrodes 334, 335 can be arranged in 32 pairs (or bipolar electrodes).

[0069] It is understood that FIGS. 3A -3E illustrates a specific example of the stacked configuration of a shank 330 and that the positional and structural relationships between the layers 332a-332f, the traces 333, and / or the electrodes 334, 335 can vary / deviate from that shown. For example, shanks configured in accordance with other embodiments of the present technology can include a greater or lesser number (e.g., one, two, three, or more than four) of thin film layers that are similar to the thin film layers 332a-332d, a greater or lesser number oftraces 333 per layer, and / or a greater or less number of electrodes 334 and / or 335. As such, alternative embodiments of the present technology can have any desired number of layers, traces, and electrodes. As a specific example, shanks of the present technology can include one or more stacked, thin, non-conductive layers, with each layer including at least one trace deposited thereon.

[0070] According to some embodiments, a shank can be produced by coating, layering, or cladding separate non-conductive layer panels (also referred to as “sheets”) with a conductive material. For example, in one embodiment, sheets can be coated with copper, gold, or another suitable conductive material. The conductive coating on each separate sheet can then be coated with a photoresist material (e.g., SU-8). Thereafter, the photoresist layer can be exposed to an image of a desired electrically conductive pattern. After exposure, the unexposed photoresist material and underlying portions of the conductive coating can be removed, thereby leaving each sheet with conductive traces disposed thereon in the desired layout. A desired number of separate sheets with conductive traces can then be stacked or otherwise positioned on each other to form a body of the shank.

[0071] In some embodiments, one or more cover layers can be positioned on, under, and / or about the body of the shank. Electrodes can then be formed by creating openings within the cover layers to expose ends of the conductive traces formed on the sheets such that the ends of the conductive traces are in fluid communication with the corresponding openings in the cover layers. Conductive material corresponding to electrodes can then be deposited in the openings and placed in electrical contact with ends of the conductive traces. Conductive material corresponding to electrodes can be deposited in the openings via a deposition process. More specifically, in one embodiment, the electrodes can be deposited via edge plating. Alternatively, each of the electrodes can be positioned or disposed on the body via another suitable method or process.

[0072] As discussed above, the electrodes can be formed of any suitable conductive, biocompatible material, such as platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, gold, copper, or the like. In some embodiments, the conductive material corresponding to the electrodes can be deposited in the openings in the cover layers such that the electrodes are flush with or recessed below a top, outward-facing surface of the corresponding cover layer. Alternatively, the conductive material corresponding to the electrodes can be deposited in the openings in the cover layers such that the electrodes project outward a distancebeyond the top, outward-facing surface of the corresponding cover layer. In such embodiments, the electrodes can extend from about 0 microns to about 12 microns out from the top, outwardfacing surface, such as about 2 microns to about 10 microns, about 4 microns to about 8 microns, or the like. The electrodes can be formed with any suitable shape or cross-section, including a circle, oval, square, rectangle, quadrilateral, or any other known shape.

[0073] FIGS. 17A-17C are partially schematic diagrams illustrating steps for fabricating an electrode shank 1730 (FIG. 17C) in accordance with various embodiments of the present technology. For the sake of clarity and explanation, only a distal end portion 1741 of the electrode shank 1730 (“the shank 1730”) is shown in FIGS. 17A-17C. With the exception of formation of electrodes 1734, 1735 and traverse portions 1733b in the distal end portion 1741, a proximal end portion 1742 of the shank 1730 can largely be formed consistent with the following description. The electrode shank 1730 (“the shank 1730”) can be an example of the shank 330 of FIGS. 3A-3E, or of other electrode shanks configured in accordance with various embodiments of the present technology (e.g., one or more of the electrode shanks 430, 530, 630a-630e, 1130, and / or 1230 described in greater detail below with reference to FIGS. 4A-4C, 5, 6A-6C, 11, 12A, and 12B, respectively). Thus, similar reference numbers are used across FIGS. 3A-3E and 17A-17C to denote identical or at least generally similar components.

[0074] Referring to FIG. 17A, a sacrificial layer 1745 can be deposited on a substrate (not shown). The sacrificial layer 1745 can be deposited using any suitable technique, such as sputtering, evaporation, electroplating, or the like. In some embodiments, the sacrificial layer 1745 can be formed of nickel or another suitable material.

[0075] After formation of the sacrificial layer 1745, a first insulation layer 1732e can be formed on the sacrificial layer 1745 with a plurality of discrete electrodes 1734 (also referred to herein as “contacts,” “electrode pads,” and the like) disposed therein or thereon. Two electrodes 1734 (identified individually in FIG. 17A as first electrode 1734a and second electrode 1734b) are shown in the illustrated embodiment, but it is appreciated that any suitable number of electrodes 1734 (e.g., one or more than two electrodes 1734) can be disposed in or on the first insulation layer 1732e. The first insulation layer 1732e can be formed of a photoresist (e.g., SU- 8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. Additionally, or alternatively, the electrodes 1734 can be formed of a biocompatible material, such as platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, gold, copper,nitinol, or another suitable conductive material. In some embodiments, the first insulation layer 1732e can serve as a cover layer.

[0076] In a specific example, conductive material corresponding to the electrodes 1734 can be deposited using sputtering, evaporation, or another suitable technique. Photolithography and etching can thereafter be used to define the electrodes 1734, and spaces between the electrodes 1734 can be filled using a material corresponding to the first insulation layer 1732e.

[0077] In another specific example, the electrodes 1734 can be formed using a liftoff process. More specifically, a photoresist material can be deposited on the sacrificial layer 1745 and patterned (e.g., using photolithography and etching) to define locations for the electrodes 1734 in the photoresist material. Conductive material corresponding to the electrodes 1734 can then be deposited over the patterned photoresist. Remaining photoresist can serve as the first insulation layer 1732e, or the remaining photoresist can be removed and spaces between the electrodes 1734 can be filled using a material corresponding to the first insulation layer 1732e.

[0078] Referring now to FIG. 17B, a second insulation layer 1732a can be formed on or over the first insulation layer 1732e and / or the electrodes 1734. For example, the second insulation layer 1732a can be deposited on the first insulation layer 1732e and / or the electrodes 1734 using spin coating, dip coating, spray coating, or another suitable method. The second insulation layer 1732a can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. In a specific example, the second insulation layer 1732a can be formed of polyimide. Continuing with this example, the second insulation layer 1732a can be applied on or over the first insulation layer 1732e and / or the electrodes 1734 using any suitable technique, and thereafter cured to form a stable insulation layer.

[0079] A first interconnect layer 1738a comprising a first set of conductive traces 1733A can be formed on or over the second insulation layer 1732a. As discussed above, individual traces 1733 can include an elongated portion 1733a and a corresponding traverse portion 1733b. Two traces 1733 are shown in FIG. 17B with corresponding elongated portions 1733a- 1 , 1733a- 2 and traverse portions 1733b-l , 1733b-2.

[0080] In some embodiments, the elongated portions 1733a of the first set of conductive traces 1733A can be formed by coating the second insulation layer 1732a with a conductive material corresponding to the elongated portions 1733a. The conductive material can be a same material as, or a different material from, the material used to form the electrodes 1734. Forexample, the conductive material can be platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, copper, gold, nitinol, or another suitable conductive material.

[0081] The coating of conductive material can then be patterned using photolithography followed by electroplating or evaporation. As a specific example, the conductive coating can be coated with a photoresist material (e.g., SU-8). Thereafter, the photoresist layer can be exposed to an image of a desired electrically conductive pattern. After exposure, the unexposed photoresist material and underlying portions of the conductive coating can be removed, thereby leaving each sheet with conductive traces disposed thereon in the desired layout. Spaces between the elongated portions 1733a can be filled using an insulative material, such as a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film.

[0082] The traverse portions 1733b (also referred to herein as “side portions,” “vias,” or the like) can each be formed between a corresponding one of the electrodes 1734 and a distal end portion of a corresponding one of the elongated portions 1733a of the first set of conductive traces 1733 A. For example, the traverse portions 1733b can be formed using reactive ion etching (RIE) or another suitable technique. The traverse portions 1733b can be formed of a same material as, or a different material from, the elongated portions 1733a and / or the electrodes 1734. For example, the traverse portions 1733b can be formed of platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, copper, gold, nitinol, or another suitable conductive material.

[0083] After formation of first interconnect layer 1738a and corresponding traces 1733 of the first set of conductive traces 1733A, a third insulation layer 1732b can be formed on or over the first interconnect layer 1738a. For example, the third insulation layer 1732b can be deposited on the first interconnect layer 1738a using spin coating, dip coating, spray coating, or another suitable method. The third insulation layer 1732b can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. Tn a specific example, the third insulation layer 1732b can be formed of polyimide. Continuing with this example, the third insulation layer 1732b can be applied on or over the first interconnect layer 1738a using any suitable technique, and thereafter cured to form a stable insulation layer.

[0084] A second interconnect layer 1738b comprising a second set of conductive traces 1733B can be formed on or over the third insulation layer 1732b. The second interconnect layer 1738b and the second set of conductive traces 1733B can be formed in a manner generallyconsistent with the description of the first interconnect layer 1738a and the first set of conductive traces 1733A, respectively, above.

[0085] Referring now to FIG. 17C, fourth insulation layer 1732g can be formed on or over the second interconnect layer 1738b. For example, the fourth insulation layer 1732g can be deposited on the second interconnect layer 1738b using spin coating, dip coating, spray coating, or another suitable method. The fourth insulation layer 1732g can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. In a specific example, the fourth insulation layer 1732g can be formed of polyimide. Continuing with this example, the fourth insulation layer 1732g can be applied on or over the second interconnect layer 1738b using any suitable technique, and thereafter cured to form a stable insulation layer. In some embodiments, the fourth insulation layer 1732g can serve as a central insulation layer (e.g., demarcating a top and bottom half of the shank 1730 and / or helping to ensure electrical isolation between immediately adjacent interconnect layers).

[0086] A third interconnect layer 1738c comprising a third set of conductive traces 1733C can be formed on or over the fourth insulation layer 1732g. The third interconnect layer 1738c and the third set of conductive traces 1733C can be formed in a manner generally consistent with the description of the first and second interconnect layers 1738a, 1738b and the first and second sets of conductive traces 1733A, 1733B, respectively, above.

[0087] In some embodiments, the traverse portions 1733b of the third set of conductive traces 1733C can be formed after formation of a fifth insulation layer 1732c, a fourth interconnect layer 1738d, a sixth insulation layer 1732d, and / or a seventh insulation layer 1732f described below. For example, the traverse portions 1733b of the third set of conductive traces 1733C can be formed prior to (e.g., immediately prior to) or during formation of electrodes 1735 in or on the seventh insulation layer 1732f. As a specific example, the traverse portions 1733b of the third set of conductive traces 1733C can be formed by (a) forming a recess in the fifth insulation layer 1732c, the fourth interconnect layer 1738d, the sixth insulation layer 1732d, and / or the seventh insulation layer 1732f; and (b) filling the recess with conductive material to form the traverse portions 1733b, such as before depositing material corresponding to the electrodes 1735 and / or while depositing material corresponding to the electrodes 1735.

[0088] Alternatively, the traverse portions 1733b of the third set of conductive traces 1733C can be formed in sections or portions, such as part of formation of the fifth insulation layer 1732c, the fourth interconnect layer 1738d, the sixth insulation layer 1732d, and / or theseventh insulation layer 1732f described below (e.g., using photolithography, etching, liftoff, and REI processes).

[0089] The fifth insulation layer 1732c can be formed on or over the third interconnect layer 1738c. For example, the fifth insulation layer 1732c can be deposited on the third interconnect layer 1738c using spin coating, dip coating, spray coating, or another suitable method. The fifth insulation layer 1732c can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. In a specific example, the fifth insulation layer 1732c can be formed of polyimide. Continuing with this example, the fifth insulation layer 1732c can be applied on or over the third interconnect layer 1738c using any suitable technique, and thereafter cured to form a stable insulation layer.

[0090] The fourth interconnect layer 1738d comprising a fourth set of conductive traces 1733D can be formed on or over the fifth insulation layer 1732c. The fourth interconnect layer 1738d and the fourth set of conductive traces 1733D can be formed in a manner generally consistent with the description of the first and third interconnect layers 1738a, 1738c and the first and third sets of conductive traces 1733A, 1733C, respectively, above.

[0091] The sixth insulation layer 1732d can be formed on or over the fourth interconnect layer 1738d. For example, the sixth insulation layer 1732d can be deposited on the fourth interconnect layer 1738d using spin coating, dip coating, spray coating, or another suitable method. The sixth insulation layer 1732d can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. In a specific example, the sixth insulation layer 1732d can be formed of polyimide. Continuing with this example, the sixth insulation layer 1732d can be applied on or over the third interconnect layer 1738c using any suitable technique, and thereafter cured to form a stable insulation layer.

[0092] The seventh insulation layer 1732f can be formed on the sixth insulation layer1732d with a plurality of discrete electrodes 1735 (also referred to herein as “contacts,” “electrode pads,” and the like) disposed therein or thereon. Two electrodes 1735 (identified individually in FIG. 17C as first electrode 1735a and second electrode 1735b) are shown in the illustrated embodiment, but it is appreciated that any suitable number of electrodes 1735 (e.g., one or more than two electrodes 1735) can be disposed in or on the seventh insulation layer 1732f. For example, a same number of electrodes 1735 or a different number of electrodes 1735 can be disposed in or on the seventh insulation layer 1732f as the number of electrodes 1734 that are disposed in or on the first insulation layer 1732e. Additionally, or alternatively, electrodes1735 can be disposed in or on the seventh insulation layer 1732f such that at least some of the electrodes 1735 are vertically aligned with electrodes 1734 disposed in or on the first insulation layer 1732e (as is shown in the illustrated embodiment), or the electrodes 1735 can be disposed in or on the seventh insulation layer 1732f such that at least some of the electrodes 1735 are vertically out of alignment with electrodes 1734 disposed in or on the first insulation layer 1732e.

[0093] The seventh insulation layer 1732f can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. Additionally, or alternatively, the electrodes 1735 can be formed of a biocompatible material, such as platinum, platinum-iridium, titanium nitride, tantalum, tantalum pentoxide, gold, copper, nitinol, or another suitable conductive material. In some embodiments, the seventh insulation layer 1732f can serve as a cover layer. In these and other embodiments, the seventh insulation layer 1732f can be formed using a same material as, or a different material from, the material used to form the first insulation layer 1732e.

[0094] In a specific example, conductive material corresponding to the electrodes 1735 can be deposited on the sixth insulation layer 1732d using sputtering, evaporation, or another suitable technique. Photolithography and etching can thereafter be used to define the electrodes 1735, such as at locations over traverse portions 1733b of corresponding conductive traces 1733 of the third and fourth sets of conductive traces 1733C, 1733D. Spaces between the electrodes 1735 can be filled using a material corresponding to the seventh insulation layer 17321'.

[0095] In another specific example, the electrodes 1735 can be formed using a liftoff process, such as at locations over traverse portions 1733b of corresponding conductive traces 1733 of the third and fourth sets of conductive traces 1733C, 1733D. More specifically, a photoresist material can be deposited on the sixth insulation layer 1732d and patterned (e.g., using photolithography and etching) to define locations for the electrodes 1735 in the photoresist material. Conductive material corresponding to the electrodes 1735 can then be deposited over the patterned photoresist. Remaining photoresist can serve as the seventh insulation layer 1732f, or the remaining photoresist can be removed and spaces between the electrodes 1735 can be filled using a material corresponding to the seventh insulation layer 1732f.

[0096] The electrode shank 1730 can thereafter be released from the sacrificial layer 1745. For example, the sacrificial layer 1745 can be released using a suitable etchant, such as a nickel etchant in embodiments in which the sacrificial layer 1745 is formed of nickel. The resulting electrode shank 1730 is a free-standing, flexible structure having electrodes on both a top surfaceand bottom surface. More specifically, the electrode shank 1730 of the illustrated embodiment includes four interconnect layers 1738a-1738d, five internal insulation layers 1732a-1732d and 1732g, and two electrode-in-insulation layers 1732e and 1732f. The integration of (e.g., polymer) insulation layers is expected to ensure structural flexibility and electrical insulation. The electrodes 1734, 1735 can be exposed at or through the bottom surface and the top surface, respectively. Alternatively, the electrodes 1734, 1735 can be embedded with and covered by the first insulation layer 1732e and the seventh insulation layer 1732f, respectively.

[0097] Although shown with a specific number of electrodes 1734, 1735, interconnect layers 1738a-1738d, internal insulation layers 1732a-1732d and 1732g, and electrode-in- insulation layers 1732e and 1732f, the electrode shank 1730 can include any number of any one or more of these components in other embodiments of the present technology. Additionally, or alternatively, the electrodes 1734 or the electrodes 1735 can be omitted from the shank 1730 in other embodiments of the present technology. In these and other embodiments, the shank 1730 can include one or more electrodes on one or more other surfaces of the shank 1730 besides the top and bottom surfaces as shown in FIGS. 17C. For example, the shank 1730 can include one or more electrodes on one or more side surfaces that extend at least partway between the top surface and the bottom surface. Furthermore, although the electrode shank 1730 is illustrated as being symmetric about the fourth insulation layer 1732g in FIG. 17C, the electrode shank 1730 need not be symmetric in other embodiments of the present technology.

[0098] Moreover, although the third interconnect layer 1738c, the fifth insulation layer 1732c, the fourth interconnect layer 1738d, the sixth insulation layer 1732d, and the seventh insulation layer 1732f are described above as being formed on or over the portion of the shank 1730 shown in FIG. 17B, these layers of the shank 1730 can be formed separately from the portion of the shank 1730 shown in FIG. 17B. For example, two instances of the portion of the shank 1730 can be separately formed. Thereafter, the two instances can be attached to one another, such as by adhering or affixing the second interconnect layer 1738b and the third interconnect layer 1738c to one another using an insulating adhesive. Continuing with this example, the fourth insulation layer 1732g can be an insulating adhesive in at least some of these embodiments.

[0099] The fabrication processes described above with reference to FIGS. 17A-17C are expected to offer several advantages. For example, these fabrication processes are expected to (a) optimize spatial density of conductive traces for planar fabrication with right-angle patterns,(b) achieve consistent or uniform distances in three-dimensions between adjacent conductive traces, and (c) maintain electrical isolation of the conductive traces from one another using insulative material positioned between adjacent conductive traces. These fabrication processes are also expected to optimize spatial density of active sites in the brain by, for example, positioning electrodes on both the top and bottom surfaces of a shank. Additionally, or alternatively, these fabrication processes are expected to be usable to produce the structurally symmetric electrode shanks. Such structural symmetry is expected to result in stronger resistance of a shank to bending forces due to a larger section modulus and balanced loading during handling and / or insertion of the shank.

[0100] Referring again to FIGS. 3A, 3B, and 3D, the shank 330 can include a conical tip portion 336 having a hole or aperture 337 provided therein. As discussed in greater detail below with reference to FIG. 5, for assisting with inserting and positioning the shank 330 within the brain (or other tissue), one or more stylets or rods (not shown) can be removably affixed to the shank 330. For example, a stylet may be affixed to the shank 330 by inserting a distal end or tip of the stylet into the aperture 337 in the conical tip portion 336 of the shank 330. Optionally, the distal end of the stylet can be removably secured in place within the aperture 337, such as using dissolvable polyethylene glycol (PEG) or another suitable material or adhesive. In these and other embodiments, two stylets (i) can be affixed to two sides of the shank 330 (e.g., the two sides of the shank 330 that do not include the electrodes 334, 335), and (ii) can be used to assist with inserting and positioning the shank 330 within the brain or other tissue. In these and still other embodiment, the shank 330 can include a central lumen through which a stylet may be placed.

[0101] The stylet can be made of a rigid material. Examples of suitable materials include tungsten, stainless steel, or plastic. The stylet may have a handle at its proximal end to assist with inserting the shank 330 into the brain or other tissue, as well as with rotating the stylet and / or the shank 330. Other positioning and inserting means (e.g., a guidewire, a stylet inserted within a lumen of the shank, etc.) are of course possible and within the scope of this disclosure.

[0102] In some embodiments of the present technology, an electrode array of the current disclosure can include 35 shanks, with each shank including 64 electrodes arranged in 32 pairs. Continuing with this example, an electrode array can include a total of 1,120 pairs of electrodes that can be inserted into a brain hemisphere for stimulation and / or recording of a plurality of neural targets within an LGN region of the brain. In some embodiments, a second electrode arraycan include 1,120 pairs of electrodes that can be inserted into the other brain hemisphere for stimulation and / or recording of a plurality of neural targets within another LGN region of the brain.

[0103] As discussed in greater detail below, electrodes and electrode shanks (e.g., about 5 shanks to about 40 shanks, about 10 shanks to about 35 shanks, about 1 shanks to about 30 shanks, or the like) of an electrode array can be simultaneously inserted into the brain and positioned at one or more locations within the brain. As a specific example, 35 shanks of an electrode array can be inserted within the brain for stimulation and / or recording of LGN activity within one brain hemisphere.

[0104] FIGS. 4A-4C are partially schematic views of another electrode shank 430 configured in accordance with various embodiments of the present technology. More specifically, FIG. 4A is a partially schematic top planar view of the electrode shank 430; FIG. 4B is a partially schematic, partially transparent, partial cross-sectional perspective view of the electrode shank 430; and FIG. 4C is a bottom perspective view of the electrode shank 430. The electrode shank 430 (“the shank 430”) is generally similar to the shank 330 and the shank 1730 described above with reference to FIGS. 3A-3E and 17A-17C, respectively. Thus, similar reference numbers are used across FIGS. 3A-4C and 17A-17C to denote identical or at least generally similar components, and a detailed discussion of the shank 430 is largely omitted here for the sake of brevity in light of the detailed discussion provided above with references to FIGS. 3A-3E.

[0105] As shown in FIGS. 4A-4C, the shank 430 includes an active distal end region 441, a proximal end region 442 (FIGS. 4 A and 4C) opposite the active distal end region 441 , a conical tip portion 436, and an aperture 437 in the conical tip portion. Similar to the shank 330 of FIGS. 3A-3E, the shank 430 further includes a body 431 (FIGS. 4A and 4C), a plurality of electrodes 434 disposed on one side of the body 431, and a plurality of electrodes 435 disposed on another side of the body 431 opposite the electrodes 434. In some embodiments, the electrodes 434, 435 can be disposed in or on a corresponding cover layer, such as a cover layer that is similar to one of the cover layers 332e, 332f of FIGS. 3A-3E.

[0106] The body 431 of the shank 430 can include a stack (or array) of thin, non- conductive layers. Each of the layers of the body 431 can include a plurality of conductive traces 433 (FIG. 4B) formed thereon. The non-conductive layers can be formed of a photoresist (e.g., SU-8), polyimide, mylar, silicon, or another suitable biocompatible dielectric material / film. Inthese and other embodiments, conductive traces 433 formed on a non-conductive layer of the body 431 can be arranged in a single layer, and each trace 433 can extend along the length of the shank 430 between the proximal end region 442 and the distal end region 441 before branching to a corresponding one of the electrodes 434, 435.

[0107] In some embodiments, the body 431 can include a width W (FIG. 4 A) of approximately 100 microns and / or a height H (FIG. 4C) of approximately 10 microns. In these and other embodiments, an individual conductive trace 433 can include a width of approximately 500 nanometers to about 4 microns. In these and still other embodiments, traces 433 disposed on a same non-conductive layer of the body 431 can be electrically isolated from one another and / or center-spaced at approximately 4 microns. Different dimensions for the body 431 and the traces 433, and different spacings for the traces 433, are of course possible and within the scope of the present technology.

[0108] In the illustrated embodiment, the shank 430 includes 25 electrodes 434 and 25 electrodes 435. The shank 430 can include a different number (e.g., less than 25 (including zero) or more than 25) electrodes 434 and / or a different number (e.g., less than 25 (including zero) or more than 25) electrodes 435 in other embodiments of the present technology. In some embodiments, the electrodes 434, 435 can each include a width of approximately 50 microns. In these and other embodiments, the electrodes 434 can be center-spaced at approximately 130 microns, and / or the electrodes 435 can be center-spaced at approximately 130 microns. Other dimensions and / or spacings for the electrodes 434, 435 are of course possible and within the scope of the present technology.

[0109] A person of ordinary skill in the art will appreciate that a greater number of stimulation sites within an LGN region can produce better resolution in the artificial sensation of vision provided to a subject. Thus, electrode arrays of the present technology can include any number of electrodes, any number of bipolar electrodes, any number of electrode shanks, and / or any number of electrode array groupings. As a specific example, an electrode array implantable into one brain hemisphere can include 4,000 or more electrodes. Continuing with this specific example, the electrodes can be arranged into 2,000 (or another suitable number) of bipolar electrodes. The 4,000 electrodes can be distributed across about 5 to about 50 electrode shanks, such as about 8 to about 25 shanks, about 10 to about 20 shanks, about 11 to about 15 shanks, or the like. In some embodiments, the electrode shanks can be arranged in one or more electrode array groups for simultaneous insertion into the brain or other tissue. For example, the electrodeshanks can be arranged into about 5 to about 25 electrode array groups, such as about 7 to about 20 electrode array groups, about 9 to about 15 electrode array groups, about 11 to about 13 electrode array groups, or the like.Electrode Array Insertion Devices

[0110] Electrode shanks (e.g., the shank 330 of FIG. 3A-3E, the electrode shank 430 of FIGS. 4A-4C, the shank 1730 of FIGS. 17A-17C) of the present technology can be ultra-thin and flexible. Thus, the present technology can include a variety of insertion devices that can be used to assist with implanting the electrode shanks of an electrode array at desired locations within the brain or other tissue, such as within an LGN region of the brain. For example, as discussed above, the insertion devices can include stylets or rods that are each configured to interface with an aperture at or near a distal end of an electrode shank. As a specific example, FIG. 5 is a partially schematic perspective view of an electrode shank 530 interfacing with such a stylet 550. More specifically, a distal end 555 of the stylet 550 is seated within an aperture 537 in a conical tip portion 536 of the electrode shank 530, and a body 531 of the electrode shank 530 is adhered to an elongated body portion 551 of the stylet 550 such that the body 531 of the shank 530 is held in a generally straight and / or flat orientation. The electrode shank 530 can be an example of the electrode shank 330 of FIGS. A-3E, the electrode shank 430 of FIGS. 4A- 4C, the electrode shank 1730 of FIGS. 17A-17C or of other electrode shanks configured in accordance with various embodiments of the present technology.

[0111] As shown in FIG. 5, the conical tip portion 536 of the electrode shank 530 is flexible and can be bent out of alignment with the elongated body 531 of the shank 530. This can allow the stylet 550 to be offset by approximately 10 microns (or another suitable distance) from the back of the shank 430 when the distal end 555 of the stylet 550 is seated within the aperture 537 and the body 531 of the shank 530 is adhered to the elongated body portion 551 of the stylet 550. Such an offset away from the back of the shank 530 can reduce the likelihood of the stylet 550 damaging electrodes 534, 535 (not shown) of the shank 530 during assembly of the arrangement shown in FIG. 5, during assembly of an electrode array group arrangement (described in greater detail below with reference to FIGS. 6A-6C), and / or during implantation of the shank 530 within the brain or other tissue.

[0112] In some embodiments, the stylet 550 can be formed of tungsten, stainless steel, plastic, or another suitable material. In these and other embodiments, the distal end 555 of the stylet 550 can include a machine-tapered tip. In these and still other embodiments, the stylet 550can include a diameter of approximately 50 microns and / or can include a length of approximately 10 mm. Other diameters and lengths for the stylet 550 are of course possible and within the scope of the present technology.

[0113] In some embodiments, the distal end 555 of the stylet 550 can be held within the aperture 537 of the conical tip portion 536 of the shank 530 using dissolvable polyethylene glycol (PEG) or another suitable material or adhesive. Additionally, or alternatively, the body 531 of the shank 530 can be adhered to the elongated body portion 531 of the stylet 550 using dissolvable PEG or another suitable material or adhesive. Thus, in these embodiments, the shank 530 can be held against the stylet 550 in a generally straight orientation (e.g., during initial implantation of the shank 530 in the brain or other tissue using the stylet 550), and can be released from the stylet 550 when the PEG or other material / adhesive dissolves (e.g., a period of time after the stylet 550 and the shank 530 have been introduced within a subject’s body). Thereafter, the stylet 550 can be removed while keeping the shank 530 in place at a desired position within the brain or other tissue.

[0114] Electrode shanks (e.g., the shank 330 of FIG. 3A-3E, the electrode shank 430 of FIGS. 4A-4C) of the present technology can be individually implanted within a subject. Additionally, or alternatively, the electrode shanks can be implanted within a subject in one or more groups (e.g., groups of about two to about ten electrode shanks, such as about three to about seven electrode shanks, about four to about six electrode shanks, or five electrode shanks). For example, FIGS. 6A-6C are partially schematic perspective views of an electrode array group arrangement 668 configured in accordance with various embodiments of the present technology. Referring to FIG. 6A, the electrode array group arrangement 668 (“the group arrangement 668”) includes an electrode array group 665 of five electrode shanks 630a-630e. The electrode array group arrangement 668 further includes five corresponding stylets 650a-650e, an insertion disc 660, and five corresponding sets of cables 617a-617e. Each of the electrode shanks 630a-630e can be an example of the electrode shank 330 of FIGS. 3A-3E, the electrode shank 430 of FIGS. 4A-4C, the electrode shank 530 of FIG. 5, the electrode shank 1730 of FIGS. 17A-17C, or other electrode shanks configured in accordance with various embodiments of the present technology. In addition, each of the stylets 650a-650e can be an example of the stylet 550 of FIG. 5 or other stylets configured in accordance with various embodiments of the present technology.

[0115] As shown, each of the electrode shanks 630a-630e is held in a generally straight orientation via a corresponding one of the stylets 650a-650e and in a manner generally consistentwith the discussion of FIG. 5 above. In the illustrated embodiment, the electrode shanks 630a- 630e and the corresponding stylets 650a-650e are positioned in corresponding apertures 661a- 661e formed in the insertion disc 660. The insertion disc 660 can machined PEEK, PTFE or another suitable fluoropolymer, silicone, stainless steel, or titanium. In some embodiments, the insertion disc 660 can have a height (or thickness) of approximately 100 microns and / or a diameter of approximately 1.2 mm. Other heights and diameters for the insertion disc 660 are of course possible and within the scope of the present technology.

[0116] In the illustrated embodiment, proximal ends of traces (e.g., the traces 333 of FIGS. 3A-3E, the traces 433 of FIGS. 4A-4C) in the electrode shanks 630a-630e are coupled to corresponding traces in the sets of cables 617a-617e. For example, the proximal ends of the traces in the proximal end portion of each of the electrode shanks 630a-630e can be coupled to corresponding traces in a corresponding one of the sets of cables 617a-617e via soldering to a ball grid array (not shown).

[0117] As shown, the apertures 661a-661e in the insertion disc 660 can be filled with PDMS silicone or another suitable biocompatible material. Such filling can provide additional rigidity / support to (i) the cables 617a-617e and / or (ii) the connections of traces in the cable 617a- 617e to corresponding traces in the electrode shanks 630a-630e. In some embodiments, the apertures 661a-661e can be filled with PDMS silicone or another suitable material using a custom mold. In these and other embodiments, the apertures 66 la-661 e can be filled with PDMS silicone or another suitable material in a manner that permits removal of the stylets 650a-650e proximally through the insertion disc 660 after the stylets 650a-650e are no longer adhered to the electrode shanks 630a-630e.

[0118] In some embodiments, individual ones of the cables 617a-617e can be approximately 150 microns wide and 20 microns thick, permitting use of traces in the cables 617a-617e that have a larger section modulus than the traces included in the electrode shanks 630a-630e. Use of traces with a larger section modulus is expected to (a) reduce stresses imposed when the cables 617a-617e are bent and (b) enable formation of the traces using conductive materials with higher tensile strengths. In some embodiments, the cables 617a-617e are flexible. In these and other embodiments, the cables 617a-617e can be approximately 8 to 10 cm in length. Other widths, thicknesses, and lengths for the cables 617a-617e are of course possible and within the scope of the present technology.

[0119] In some embodiments, traces in the cables 617a-617e are configured to electrically couple electrodes of a corresponding one of the electrode shanks 630a-630e to a pulse generator (e.g., the pulse generator 216a or the pulse generator 216b of FIG. 2B). For example, each of the cables 617a-617e can extend from a third cable stage (not shown), through a bushing in a subject’s skull, and to the proximal end of a corresponding one of the electrode shanks 630a- 630e. More specifically, each of the cables 617a-617e can include traces having (i) proximal ends configured to remain external to the subject’s skull, beneath the scalp, and (ii) distal ends opposite the proximal ends. The distal ends of the traces in the cables 617a-617e are configured to be inserted / implanted within the subject and can be coupled to proximal ends of traces in the electrode shanks 630a-630e. The proximal ends of the traces in the cables 617a-617e can interface with a third cable stage (not shown). The third cable stage (i) can be shared by the set of cables 617a-617e and / or by cables corresponding to other electrode array groups, and (ii) can be usable to couple traces in the cables 617a-617e to a pulse generator. In some embodiments, a bushing through which the cables 617a-617e extend can include a slot that is usable for routing the cables 617a-617e from within the subject and toward the pulse generator. Additionally, or alternatively, the bushing can include a cover plate or cap that is usable to secure the cables 617a-617e in place (e.g., to provide strain relief) after the prosthesis is implanted.

[0120] In some embodiments, the interface between the cables 617a-617e and the third cable stage can be modular. For example, the proximal ends of the cables 617a-617e and the third cable stage can interface with one another via a dual-sided flat flexible connector (not shown). This can enable revision and / or replacement of individual electrode shanks (e.g., individual ones of the electrode shanks 630a-630e) and / or individual electrode array groups (e.g., the electrode array group 665) without modifying or exposing the pulse generator. In some embodiments, a zero-insertion force clip (not shown) can be used with the flat flexible connector.

[0121] Although described above as having three cable stages (e.g., a first cable trace including traces within the electrodes shanks 630a-630e, a second cable stage corresponding to the cables 617a-617e, and a third cable stage extending from a pulse generator to an interface (e.g., a flat flexible connector) between the second cable stage and the third cable stage), any number of cable stages can be used. For example, in some embodiments, the cables 617a-617e can extend a full distance between the pulse generator and proximal ends of traces in the electrode shanks 630a-630e. In at least some of these embodiments, the cables 617a-617e can be directly coupled to the pulse generator. As another example, the traces in the electrode shanks 630a-630e can be directly coupled to the pulse generator, and extend a full distance between thepulse generator and the electrode shanks 630a-630e. As still another example, a pulse generator can wirelessly communicate with electrodes of the electrode shanks 630a-630e. Continuing with this example, the electrode shanks 630a-630e can omit or lack cables that extend between proximal end portions of the electrode shanks and the pulse generator.

[0122] Referring now to FIGS. 6B and 6C, the stylets 650a-650e can he ganged together and to an insertion rod 667 via a ganging member 664 that is positioned proximal to the insertion disc 660. The insertion rod 667, the ganging member 664, and the stylets 650a-650e can collectively be referred to herein as an “insertion rod assembly” or as a “rod assembly.” In some embodiments, the ganging member 664 can be integral with the insertion rod 667. In these and other embodiments, the ganging member 664 can be integral with one or more of the stylets 650a-650e. In other embodiments, the ganging member 664 can include (a) slots, clips, recesses, or threading (not shown) that are each configured to interface with and releasably hold one of the stylets 650a-650e, and / or (b) a slot, clip, recess, or threading (not shown) that is configured to interface with and releasably hold the insertion rod 667. In some embodiments, the electrode array group arrangement 668 illustrated in FIG. 6C can be protected and covered (e.g., kept sterile) using a retractable or peel-away sheath that can be removed prior to insertion of the electrode array group 665, the stylets 650a-650e, and / or the insertion disc 660 into a grid insert, a bushing, and / or a subject.

[0123] As discussed in greater detail below, the insertion rod 667, the ganging member 664, and the stylets 650a-650e can be used to simultaneously implant the electrode shanks 630a- 630e of the electrode array group 665. For example, during insertion of the electrode array group 665 into the brain or other tissue of a subject, a distal force can be applied to the insertion rod 667 that, in turn, can be applied to the ganging member 664, the insertion disc 660, and the stylets 650a-650e. As a result, the electrode shanks 630a-630e of the electrode array group 665 can be advanced distally into the brain or other tissue. As another example, before the PEG or other material adhering the electrode shanks 630a-630e to the stylets 650a-650e has dissolved, a proximal force can be applied to the insertion rod 667 (e.g., by the surgeon, via toothed forceps, via a microdrive system, etc.) that, in turn, can be applied to the ganging member 664, the stylets 650a-650e, and the electrode shanks 630a-630e (e.g., to retract the electrode shanks 630a-630e proximally). As still another example, once (i) the electrode shanks 630a-630e of the electrode array group 665 are positioned at a desired location within the brain or other tissue and (ii) the PEG or other material adhering the electrode shanks 630a-630e to the stylets 650a-650e has dissolved, a proximal force can be applied to the insertion rod 667 (e.g., by the surgeon, viatoothed forceps, via a microdrive system, etc.) that, in turn, can be applied to the ganging member 664 and the stylets 650a-650e. As a result, the stylets 650a-650e, the ganging member 664, and the insertion rod 667 can be retracted proximally out of the subject while the electrode shanks 630a-630e of the electrode array group 665 remain in place at a desired location within the brain or other tissue of the subject.

[0124] As also discussed in greater detail below, the electrode array group 665 can be inserted into a subject through a slotted cannula or peal-away introducer, which itself can be inserted with an obturator within a larger bore channel of a grid insert. FIGS. 7A and 7B are partially schematic front and back perspective views, respectively, of a grid insert 770 configured in accordance with various embodiments of the present technology. As shown, the grid insert 770 is generally cylindrical and comprises (i) a plurality of channels 771 and (ii) mating apertures 772a-772c. As discussed in greater detail below with reference to FIGS. 9 and 10, the mating apertures 772a-772c are each configured to receive a guide rod or lead screw and to align with the guide apertures of a cranial bushing for inserting the grid insert 770 within a center channel of the bushing.

[0125] In the illustrated embodiments, the grid insert 770 includes eight channels 771. Grid inserts configured in accordance with other embodiments of the present technology, however, can include a different number of channels (e.g., less than eight or more than eight, such as about five to about 15 channels). Each of the channels 771 of the grid insert 770 can be configured to receive an electrode array group arrangement, such as the electrode array group arrangement 668 described about with reference to FIGS. 6A-6C. In some embodiments, each of the channels can be about 3 mm to about 15 mm long, such as about 5 mm to about 13 mm long, about 7 mm to about 11 mm long. In these and other embodiments, each of the channels can have a diameter equal to or greater than a diameter of an insertion disc (e.g., the insertion disc 660 of FIGS. 6A-6C) of an electrode array group, or about 1.2 mm or greater. Other channel lengths / depths and diameters are of course possible and within the scope of the present technology.

[0126] The location and angular orientation of each channel 771 can be determined based at least in part on an entry location of an electrode array group arrangement into the subject (e.g., a position of a bushing installed in a burr hole in a subject’s skull) and a location of target tissue or a target organ. For example, the location of the channels 771 within the grid insert 770 can be determined (i) based on various target neural sites within an LGN region of a subject’s brain thatneed to be stimulated or recorded and (ii) such that each channel 771 can direct an electrode array grouping (and corresponding electrodes) to and / or proximate to one or more of the target neural sites. Furthermore, the orientation of the channels 771 can be determined based on a desired trajectory of the electrode shanks in the electrode array grouping and the entry location into the subject. For example, if a determined position of a cranial bushing installed in a burr hole in a subject’s head (skull) aligns with a desired trajectory (within a threshold margin of error), the channels 771 in the grid insert 770 can be coaxially located within the grid insert 770 such that they align with an axis of the bushing when the grid insert is inserted within the bushing.

[0127] On the other hand, when a determined position of a bushing installed in a burr hole in a subject’s skull does not align with a desired trajectory, the axis of the channels 771 in the grid insert 770 can be configured to correct the trajectory of the electrode shanks by being formed at an angle with respect to the central axis of the grid insert 770 such that they are offset with respect to the axis of the channel of the bushing when the grid insert 770 is inserted within the bushing. In other words, the channels 771 in the grid insert 770 can be formed at an angle with respect to an axis of the grid insert 770 such that when the grid insert 770 is inserted coaxially into a bushing, the channels are offset at a longitudinal angle with respect to the longitudinal axis of the bushing for accurate deployment of the electrode shanks at a desired trajectory angle. The angular offset allows for an adjustment in trajectory of the electrode shanks inserted into the cranial cavity without removal and reinsertion of the bushing itself.

[0128] In some embodiments, the grid insert 770 can be custom fabricated to include the channels 771 at desired locations and orientations using any suitable method, such as 3D printing, laser cutting, CNC machining, or the like. In these and other embodiments, the grid insert 770 can be made from MRI-compatible materials and / or MRI-invisible materials, such as USP Class VI engineered plastic, ceramic, high density polymers, PEEK, titanium, nonferromagnetic materials, or the like.

[0129] In other embodiments, rather than inserting electrode shanks in groups, electrode shanks can be individually inserted into a subject using a corresponding grid insert. FIG. 8 is a partially schematic front perspective view of another grid insert 870 configured in accordance with various embodiments of the present technology. As shown, the grid insert 870 is generally similar to the grid insert 770 of FIGS. 7A and 7B. Thus, similar reference numbers are used across FIGS. 7A-8 to denote identical or at least generally similar components, and a detaileddiscussed of the grid insert 870 is largely omitted here for the sake of brevity in light of the discussion of the grid insert 770 provided above with reference to FIGS. 7A and 7B.

[0130] In contrast with the grid insert 770, the grid insert 870 of FIG. 8 includes a plurality of channels 871 having smaller diameters than the channels 771 of the grid insert 770. For example, the channels 871 of the grid insert 870 can include diameters of about 50 microns to about 300 microns, such as about 100 microns to about 250 microns, about 150 microns to about 200 microns, or the like. Other diameters are of course possible and within the scope of the present technology.

[0131] The channels 871 in the grid insert 870 can be configured to receive an individual electrode shank and a corresponding stylet. For example, an electrode shank can be threaded through a channel 871 in the grid insert 870 to any desired depth (e.g., about 5 cm to about 10 cm for deep brain targets, or less than about 5 cm for shallower targets). In some embodiments, an electrode shank may be threaded through the channel 871 by, for example, pushing the electrode shank into the channel 871 (while a stylet attached to the electrode shank provides the requisite rigidity); threading the electrode shank into the channel 871 by, for example, rotating or screwing the stylet; or another suitable method. Optionally, electrode shanks can be removably anchored in channels 871 in the grid insert 870, such as using dissolvable PEG or another suitable material / adhesive. Similar to the channels 771 in the grid insert 770 of FIGS. 7 A and 7B, the location and orientation of the channels 871 in the grid insert 870 can be tailored to deliver electrode shanks to a desired location within a subject along a desired trajectory.

[0132] As discussed above, grid inserts of the present technology can be configured to interface with a corresponding bushing, such as a cranial bushing (also referred to herein as a “cranial bolt”) positioned within a burr hole in a subject’s head. FIG. 9 is a partially schematic perspective view of a bushing 980 configured in accordance with various embodiments of the present technology. In some embodiments, the bushing 980 can be made of MRI-transparent and MRI-compatible materials such as, USP Class VI engineered plastic, ceramic, high density polymers, PEEK, titanium, non-ferromagnetic materials, or the like.

[0133] As shown, the bushing 980 includes a distal end portion 983 and a proximal end portion 984 on a side of the bushing opposite the distal end portion 983. In some embodiments, the distal end portion 983 can include threading (not shown), such as to thread the bushing 980 into a burr hole formed in a subject’s head. In other embodiments, the distal end portion 983 can lack or omit threading (e.g., to insert the bushing 980 into a subject’s skull in a seamless manner,such as when the skull wall is too thin to use a threaded distal end portion 983). Optionally, the proximal end portion 984 of the bushing 980 can be dimensioned such that multiple bushings can be placed in close proximity to one another.

[0134] The bushing 980 of FIG. 9 further includes a central passageway or channel 981 that extends along a length of the bushing 980 (e.g., an entire distance between the proximal end portion 984 and the distal end portion 983). In the illustrated embodiment, the channel 981 has a generally circular cross section. In other embodiments, the channel 981 can have a cross section of another geometric shape, such as a triangle, square, hexagon, or pentagon. In some embodiments, an internal diameter of the channel 981 at the proximal end portion 984 can be sized to accept a grid insert (e.g., the grid insert 770 of FIGS. 7A and 7B, the grid insert 870 of FIG. 8).

[0135] As shown, an outer section of the proximal end portion 984 of the bushing can include a rim portion 986. When the bushing 980 is positioned within a burr hole in a subject’s head, the rim portion 986 can be positioned outside the skull surface and provide a hermetic seal. The rim portion 986 can include one or more apertures 985a-985c. Each of the apertures 985a- 985c can be configured to receive anchoring tools, such as MRI-transparent, ceramic, or carbon PEEK cortical bone screws for anchoring the bushing 980 to a subject’s skull.

[0136] In some embodiments, the rim portion 986 can further include one or more alignment apertures 987 (e.g., channels, recesses, cutouts). Three alignment apertures 987a-987c are shown in the illustrated embodiment. The alignment apertures 987a-987c can be positioned generally about a periphery of the center channel 981 or bore, and / or can be oriented such that they are coaxially aligned with the channel 981.

[0137] Each of the alignment apertures 987a-987c can be configured to receive alignment cannulas or other tools. The alignment cannulas and / or other tools can comprise fiducial markers (e.g., radiopaque markers, MRI visible fluids, etc.). For example, an alignment cannula or another tool (e.g., a plastic screw) that is positionable within one of the alignment apertures 987a-987c can include an MRI-visible fluid, such as gadolinium or vitamin E. The alignment cannulas or other tools can be built into the bushing 980 (e.g., permanently positioned within a corresponding one of the alignment apertures 987a-987c). Alternatively, the alignment cannulas or other tools can be removably positioned within the alignment apertures 987a-987c. As discussed in greater detail below with reference to FIG. 13, the alignment cannulas or other toolscan facilitate determining a position and / or orientation / trajectory of the channel 981 of the bushing 980.

[0138] An internal diameter of the channel 981 at the distal end portion 983 of the bushing 980 can be sized such that an electrode array comprising one or more electrode shanks and / or one or more groups of electrode shanks can pass through the channel 981 and into the subject’s brain or other tissue. In these and other embodiments, an outer diameter of the distal end portion 983 of the bushing 980 can be sized to prevent injuries to the subject’s skull and / or to minimize a diameter of a burr hole that is drilled into the subject’s skull to receive the bushing 980.

[0139] As shown, the bushing 980 can further include one or more guide apertures 982a- 982c formed in a portion of the bushing 980 between the channel 981 and the rim portion 986 at or proximate to the proximal end portion 984 of the bushing 980. Optionally, the guide apertures 982a-982c can extend partway from the proximal end portion 984 to the distal end portion 983 along the length of the channel 981. As discussed in greater detail below with reference to FIG. 10, the guide apertures 982a-982c can be configured to guide the insertion and positioning of a grid insert into the channel 981 of the bushing 980, such as using one or more guide rods and / or lead screws.

[0140] FIG. 10 is a partially schematic perspective view of a microdrive system 1090 configured in accordance with various embodiments of the present technology. As shown, the microdrive system 1090 (“the system 1090”) includes a grid insert 1070, a bushing 1080, guide rods 1092a and 1092b, and a lead screw 1095. The grid insert 1070 can be an example of the grid insert 770 of FIGS. 7A and 7B, the grid insert 870 of FIG. 8, or other grid inserts configured in accordance with various embodiments of the present technology. In addition, the bushing 1080 can be an example of the bushing 980 of FIG. 9 or other bushings configured in accordance with various embodiments of the present technology.

[0141] In some embodiments, the lead screw 1095 can be a micro miniature lead screw. For example, the lead screw 1095 can have an outer diameter of approximately 0.5 mm to approximately 2 mm. Additionally, or alternatively, the lead screw 1095 can include a length of approximately 10 cm. Other outer diameters and lengths for the lead screw 1095 are of course possible and within the scope of the present technology. In some embodiments, the lead screw 1095 can be formed of stainless steel or another suitable material. As discussed in greater detail below, the lead screw 1095 can include threading that is usable to drive the grid insert 1070, one or more rod assemblies, one or more electrode shanks, and / or one or more electrode array groups(i) into and / or through a center channel 1081 of the bushing 1080 and / or (ii) into the brain or other tissue.

[0142] The bushing 1080 of FIG. 10 can include a plurality of guide apertures 1082a- 1082c. In the illustrated embodiment, the guide aperture 1082a is configured to receive the lead screw 1095, and the guide apertures 1082b and 1082c are each configured to receive a respective one of the guide rods 1092a and 1092b. In some embodiments, the bushing 1080 can include locking mechanisms (e.g., quarter-turn locking mechanisms) that facilitate releasably securing the guide rods 1092a and 1092b within the guide apertures 1082b and 1082c. In these and other embodiments, the bushing 1080 can include a locking mechanism that facilitates releasably securing the lead screw 1095 within the guide aperture 1082a while permitting the lead screw 1095 to rotate. For example, the bushing 1080 can include a U-shaped collar (not shown) that can be inserted from a side portion of the bushing 1080 to hold the lead screw 1095 within the guide aperture 1082a.

[0143] As shown, after the guide rods 1092a, 1092b and the lead screw 1095 are installed in the bushing 1080, the grid insert 1070 can be installed on the guide rods 1092a, 1092b and the lead screw 1095. More specifically, the grid insert 1070 can include guide apertures 1072a-1072c that can be aligned with — and thereafter advanced distally to receive — the guide rod 1092a, the guide rod 1092b, and the lead screw 1095, respectively. In some embodiments, the grid insert 1070 can be slid over the guide rods 1092a, 1092b and the lead screw 1095 until (a) the portions of the grid insert 1070 that correspond to the guide apertures 1072a- 1072c are seated within recessed portions in the bushing 1080 that correspond to the guide apertures 1082a-1082c, respectively, and (b) a body portion 1073 of the grid insert 1070 is positioned within the center channel 1081 of the bushing 1080. In other embodiments, when the grid insert 1070 is installed on the guide rods 1092a, 1092b and the lead screw 1095, the grid insert 1070 can be advanced distally toward the bushing 1080 by rotating the lead screw 1095 in a first direction. Additionally, or alternatively, the grid insert 1070 can be retracted proximally away from the bushing 1080 by rotating the lead screw 1095 in a second direction opposite the first direction. In some embodiments, the grid insert 1070 can be held in place in the center channel 1081 of the bushing 1080 via friction, compression fitting, or the like.

[0144] In some embodiments, electrode shanks and / or electrode array groups can be threaded and preassembled within one or more channels 1071 of the grid insert 1070 before the grid insert 1070 is inserted into the bushing 1080. In such embodiments, the electrode shanksand / or the electrode array groups can be inserted to a depth within the channel(s) 1071 that confines distal tips of the electrode shanks within the grid insert 1070 (e.g., to protect the electrode shanks from damage during handling and / or insertion of the grid insert 1070 within the bushing 1080). Additionally, or alternatively, when electrode shanks and / or electrode array groups are preassembled within one or more channels 1071 of the grid insert 1070, the electrode shanks and / or the electrode array groups can be inserted into the center channel 1081 of the bushing 1080 and / or into the brain or other tissue as part of positioning the grid insert 1070 into the center channel 1081. In these and other embodiments, electrode shanks and / or electrode array groups can be threaded through one or more channels 1071 of the grid insert 1070 after the grid insert 1070 is positioned within the center channel 1081 of the bushing 1080.

[0145] In some embodiments, electrode shanks and / or electrode array groups can be loaded into one or more channels 1071 of the grid insert 1070 using one or more stylets (e.g., the stylet 550 of FIG. 5, one or more of the stylets 650a-650e of FIGS. 6A-6C) and / or rod assemblies (e.g., the stylets 650a-650e, the ganging member 664, and the insertion rod 667 of FIGS. 6A-6C). In these and other embodiments, electrode shanks and / or electrode array groups can be loaded into one or more channels 1071 of the grid insert 1070 using a slotted cannula, a peel-away introducer, and / or an obturator.

[0146] As discussed above, electrode shanks and / or electrode array groups can be inserted in the brain or other tissue via one or more of the channels 1071 in the grid insert 1070 and the center channel 1081 in the hushing 1080. In some embodiments, individual electrode shanks and / or electrode array groups can be sequentially or simultaneously inserted into the brain or other tissue via the channels 1071 and the channel 1081. For example, electrode shanks can be inserted into the brain or other tissue sequentially, one at a time. As another example, several individual electrode shanks can be inserted into the brain or other tissue simultaneously, such as via different channels 1071 in the grid insert 1070. As still another example, electrode array groups can be inserted into the brain or other tissue sequentially, one at a time. As yet another example, several electrode array groups can be inserted into the brain or other tissue simultaneously, such as via different channels 1071 in the grid insert 1070.

[0147] As discussed above, the electrode shanks and / or electrode array groups can be inserted into the brain or other tissue using one or more stylets and / or rod assemblies. As a specific example, an electrode array group arrangement (e.g., the electrode array group arrangement 668 of FIGS. 6A-6C) can include a carrier rod assembly that is usable to load acorresponding electrode array group into one of the channels 1071 of the grid insert 1070. The carrier rod assembly can include (i) stylets attached to / engaged with corresponding electrode shanks of the electrode array group, (ii) an insertion rod, and (iii) a ganging member positioned proximal to an insertion disc and / or used for ganging the stylets to one another and to the insertion rod.

[0148] Continuing with this example, electrode shanks of the electrode array group arrangement can be inserted into the brain or other tissue using the carrier rod assembly. More specifically, the insertion rod can be mechanically coupled to the lead screw 1095 via a shuttle (not shown). In some embodiments, the shuttle includes one or more guide apertures that align with the guide rod 1092a and / or the guide rod 1092b. In these and other embodiments, the shuttle can include threading that engages with corresponding threading on the lead screw 1095. After the insertion rod is coupled to the lead screw via the shuttle, the lead screw 1095 can be turned in a first direction to advance the rod assembly (and therefore the electrode array group attached to the rod assembly) distally (i) along the lengths of the guide rods 1092a, 1092b and the lead screw 1095 and / or (ii) into the brain or other tissue via one of the channels 1071 in the grid insert 1070 and the center channel 1081 in the bushing 1080. Additionally, or alternatively, the lead screw 1095 can be turned in a second direction (opposite the first direction) to retract the rod assembly proximally (a) along the lengths of the guide rods 1092a, 1092b and the lead screw 1095 and / or (b) out of the brain or other tissue via one of the channels 1071 in the grid insert 1070 and the center channel 1081 in the bushing 1080. Assuming the PEG or other adhesive holding electrode shanks of the electrode array group to the stylets of the rod assembly has not yet dissolved, turning the lead screw 1095 in the second direction can also retract the electrode shanks of the electrode array group proximally with the rod assembly. The shuttle can be used to insert electrode shanks of one or more electrode array group arrangements one electrode array group arrangement at a time or multiple electrode array group arrangements at a time.

[0149] In some embodiments, turning of the lead screw 1095 of the microdrive system 1090 can be performed manually (e.g., by a surgeon). In other embodiments, turning of the lead screw 1095 can be automated, such as using a motor. In still other embodiments, insertion and / or retraction of (i) an electrode shank, (ii) an electrode array group, (ii) a grid insert, and / or (iv) a rod assembly can be performed manually (e.g., by a surgeon), such as without using the microdrive system 1090 of FIG. 10 and / or without turning of the lead screw 1095.

[0150] After electrode shanks of an electrode array have been implanted at desired locations within the brain or other tissue, the lead screw 1095, the guide rods 1092a, 1092, and / or the grid insert 1070 can be removed from the bushing 1080. Thereafter, in the event that one or more additional electrode shanks and / or electrode array groups need to be inserted within the brain or other tissue, the lead screw 1095, the guide rods 1092a, 1092, and / or a grid insert 1070 can again be installed in the bushing 1080 and used in a manner consistent with the discussion above. Additionally, or alternatively, in the event that an electrode shank and / or an electrode array group needs to be removed from within the brain or other tissue (e.g., after removal of the corresponding rod assembly), the lead screw 1095, the guide rods 1092a, 1092, and / or a grid insert 1070 can again be installed in the bushing 1080. Thereafter, cables (e.g., all or a subset of the cables 617a-617e of FIGS. 6A-6C) corresponding to the electrode shank and / or electrode array group can be mechanically coupled to the lead screw 1095 (e.g., via a clamp or clip), and the lead screw 1095 can be rotated to retract the electrode shank and / or electrode array group proximally out from within the brain or other tissue and through the center channel 1081 of the bushing 1080. Alternatively, the electrode shank and / or the electrode array group can be manually removed from within the brain or other tissue by pulling proximally on the cables corresponding to the electrode shank and / or electrode array group.Electrode Array Placement

[0151] As discussed above and in greater detail below, placement of electrodes of an electrode array within an LGN region can be optimized to evoke phosphenes. For example, FIG. 11 is a partially schematic diagram illustrating an optimized electrode group layout 1175 corresponding to the grid insert 770 of FIGS. 7A and 7B, the grid insert 1070 of FIG. 10, and / or other grid inserts configured in accordance with various embodiments of the present technology. More specifically, FIG. 11 illustrates an electrode array group arrangement 1168. The electrode array group arrangement 1168 can include an electrode array group 1165, an insertion disc 1160, and a rod assembly (not shown). The electrode array group arrangement 1 168 can be identical or at least generally similar to the electrode array group arrangement 668 of FIGS. 6A-6C. For example, the electrode array group 1165 of the electrode array group arrangement 1168 can include five electrode shanks 1130, each having a plurality of electrodes 1134, 1135 coupled to corresponding cables 11 17. The electrode shanks 1130 and / or the cables 1117 can be at least partially positioned within an aperture 1161 of the insertion disc 1160.

[0152] In the illustrated embodiment, the electrode array group arrangement 1168 is positioned within a retractable sheath 1169. The retractable sheath 1169 can be removed, and the electrode array group arrangement 1 168 can be positioned within a channel of a grid insert corresponding to the optimized electrode group layout 1175 shown in FIG. 11. As discussed above and in greater detail below, the channel in the grid insert can facilitate delivering the electrode array group 1165 to a desired location within the brain or other tissue and along a desired trajectory. Seven other electrode array group arrangements can be inserted into the brain or other tissue in a similar manner via respective ones of the other channels of the grid insert corresponding to the optimized electrode group layout 1175 shown in FIG. 11.

[0153] FIGS. 12A and 12B illustrate placement of an electrode array 1220 in a right LGN region 1201 of a brain 1200 in accordance with the optimized electrode group layout 1175 of FIG. 11. More specifically, FIG. 12A illustrates a trajectory view of eight electrode array groups 1265 of the electrode array 1220, demonstrating a conformal electrode shank 1230 arrangement. FIG. 12B is another view of the right LGN region 1201 , demonstrating angle and extent of penetration of electrodes 1234, 1235 of the electrode shanks 1230 into the LGN region 1201. In the illustrated embodiment, each electrode shank 1230 includes a total of 25 electrodes 1234, 1235 such that the electrode array 1220 includes 1,000 stimulation sites (some of which are positioned within the LGN region 1201 and others of which are positioned outside of — but proximate / about — the LGN region 1201). Other numbers of electrodes (e.g. , less than 25 or more than 25 electrodes) per electrode shank and / or other numbers of stimulation sites (e.g., less than 1,000 or more than 1,000 stimulation sites) per electrode array are of course possible and within the scope of the present technology.Insertion Methods

[0154] FIG. 13 is a flowchart illustrating a method 1300 for inserting an electrode array at a target site in an organ or other tissue in accordance with various embodiments of the present technology. The method 1300 is illustrated as a series of steps or block 1302-1314. All or a subset of one or more of the blocks 1302-1304 can be executed by or using (a) one or more components of a prosthetic system (e.g., the prosthetic system 210 of FIGS. 2A and 2B) and / or (b) one or more electrode array insertion devices (e.g., one or more stylets, components of electrode array group arrangements, grid inserts, bushings, guide rods, lead screws, motors, slotted cannulas, obturators, removable sheaths, introducers, microdrive systems, etc.). In these and other embodiments, all or a subset of one or more of the blocks 1302-1304 can be automated(e.g., performed by a motor and / or computer) and / or performed manually (e.g., by a surgeon, clinician, technician, users, etc.). In addition, all or a subset of one or more of the blocks 1302- 1304 can be performed in accordance with the discussion of FIGS. 2A-12B above and in accordance with the discussion of FIGS. 14-16 below. Indeed, several of the blocks 1302-1314 of the method 1300 are discussed in detail below with reference to FIGS. 14-15E. For example, FIGS. 15A-15E illustrate several of the steps of the method 1300.

[0155] The method 1300 begins at block 1302 by determining a trajectory to a target site within an organ or other tissue. The target site can represent a desired location within the organ or other tissue at which to implant and position one or more electrodes of an electrode array. In some embodiments, determining the trajectory can include scanning the organ or other tissue to determine a location of the target site within the organ or other tissue. For example, determining the trajectory can include obtaining high-quality, pre-operative MRI (e.g., 3 Tesla) and / or CT (e.g., angiographic) images of the organ or other tissue, and determining the target site based at least in part on the images. Thereafter, determining the trajectory can include determining the trajectory using the determined location of the target site. In some embodiments, determining the trajectory can include identifying a desired (or planned) trajectory along which to insert one or more electrodes to the target site, such as from a starting point positioned outside of a subject. Additionally, or alternatively, determining the trajectory can include determining an entry point into the subject, such as a desired (or planned) site at which to create a burr hole. In these and other embodiments, determining the trajectory can include determining a trajectory that avoids blood vessels and / or other critical or sensitive areas of the organ or other tissue.

[0156] As a specific example, determining a trajectory at block 1302 can include (a) scanning a brain of a subject to determine a location of an LGN region in the brain, and (b) using the determined location of the LGN region to identify (i) a site on the subject at which to create a burr hole and (ii) a trajectory along which to introduce one or more electrodes to a target site within the LGN region, starting from the planned site for the burr hole. Continuing with this example, determining the trajectory can include optimizing the trajectory (a) to minimize potential injury to the brain and (b) to position electrodes of an electrode array at the target site in an orientation and arrangement within the LGN region that maximizes retinotopic coverage. In some embodiments, optimizing the trajectory can include determining a trajectory to the target site starting from an insertion point at the parietal-occipital junction (e.g., as opposed to using the standard dorsal trajectory common for deep brain stimulation that extends through the frontal cortex). FIG. 14 illustrates a partially schematic top view and a partially schematic side view ofsuch a trajectory 1416 through a brain 1400. The parietal-occipital junction is the medial boundary between the parietal and occipital lobes of the brain, and insertion of one or more electrodes to a target site along a trajectory that extends through this region is not expected to cause any perceptible deficits (e.g., because this region lacks eloquent cortex). In addition, a trajectory from an insertion point at the parietal-occipital junction to a target site within an LGN region of the brain extends above and parallel to (and therefore avoids) optic radiations (e.g., white-matter projections (geniculocortical and corticogeniculate fibers) connecting the LGN to the visual cortex), which is expected to avoid, reduce, or minimize the amount of damage inflicted on these critical connections when introducing one or more electrodes of an electrode array to a target site within the LGN. Furthermore, such a trajectory from an insertion point at the parietal-occipital junction to a target site within an LGN region positions electrode shanks within the LGN such that the electrode shanks are oriented generally perpendicular to, and can be used to stimulate, neurons in multiple (e.g., all LGN layers: two magnocellular layers, four parvocellular layers, and the intercalating koniocellular layers) layers of the LGN. As such, this trajectory can maximize coverage of the respective visual hemi-fields and permit independent stimulation of the different layers of the LGN. In turn, this can enable refinement of percepts based on known anatomy to, for example, create colored percepts (e.g., phosphenes with a characteristic perceived hue and intensity).

[0157] For the sake of clarity and understanding, a brief discussion of the creation of colored percepts using the targeting and stimulation techniques of the present technology is provided here. Stimulation delivered from one or more electrodes of an electrode array of the present technology that is implanted within an LGN region of the brain activates neurons near a given stimulation site and their downstream targets such that activating a given neuron is treated as analogous to stimulating that neuron’s receptive field in the intact visual system. Targeting magnocellular layer neurons (LGN layers I and II) will generate percepts with hues corresponding to similarly weighted (e.g., same sign, both “on” or both “off’) information from Long (L) and Medium (M) retinal cones in the normal visual system. Parvocellular neurons in layers III- VI encode largely L and M cone-opponent information, along with Short (S) cone information to varying degrees, serving as the main neurons responsible for transmitting information throughout the color spectrum. Most of the S cone information is transmitted to the koniocellular neurons that intercalate and surround the main LGN layers, providing information about blue (S-on) and yellow (S-off) light.

[0158] As discussed in greater detail below, mapping procedures of the present technology can be used to create a phosphene look-up table, which is a list indexed by phosphene identifier number that is used by stimulation pattern creation software to activate desired phosphenes to create a desired percept. The phosphene mapping procedures that are employed after implantation provide information about each unique phosphene, such as geometry (location, size, and shape determined through saccade trajectories and touching a screen or pointing sphere), color (predicted by anatomical targeting but refined through verbal report and colormatching procedures, such as stimulating all “blue” phosphenes collectively and asking the subject to describe the differences amongst that subset). In the event the subject has residual vision, a custom array of phosphenes can be presented in their remaining visual field, and the subject can be asked to choose the closest match via pointing.

[0159] Referring again to FIG. 13, the method 1300 continues at block 1304 by affixing a bushing to the subject along the trajectory determined at block 1302. The bushing can be affixed to the subject using stereotactic insertion methods or one or more other suitable methods. More specifically, referring to FIG. 15A for the sake of example, affixing the bushing to the subject can include drilling a burr hole in a subject’s skull using a cranial drill. The burr hole can be located at the desired (or planned) location identified at block 1302 above and along the desired (or planned) trajectory identified at block 1302 above. Optionally, affixing the bushing can include coagulating and incising dura matter or brain covering. In these and other embodiments, affixing the bushing can include inserting or threading the bushing within the burr hole, and / or anchoring the bushing to the subject’s skull (e.g., using one or more MRI-transparent, ceramic or carbon PEEK cortical bone screws).

[0160] At block 1306, the method 1300 continues by determining positioning of the bushing with respect to the target site / location. For example, determining the positioning of the bushing can include determining the positioning of the bushing using built-in coaxial fiducial marker channels within the bushing walls to align MRI volumes with the axis of the bushing. In a related example, after inserting the bushing within the subject’s skull at block 1304, one or more alignment cannulas or other tools having fiducial markers (e.g., MRl-visible fluid) can (i) be introduced into one or more alignment apertures in the bushing and (ii) be used to determine a position and / or alignment of the bushing with respect to the trajectory determined at block 1302. For example, MRI images of the fiducial markers can be acquired and compared with known locations of the alignment apertures to determine a positioning of the bushing with respect to the desired (or planned) site / location for the burr hole that was identified at block1302. In some embodiments, the MRI acquired after bushing installation can be used to manufacture a custom grid insert for a given hemisphere. This can be done based at least in part on identified positions, orientations, sizes, and / or borders of that hemisphere’s LGN and / or bushing. For example, such information can be used to determine six spatial degrees-of-freedom (a three- valued (x, y, z) position plus an orientation expressed as rotational degrees of pitch, yaw, and roll) for grid insert apertures / channels that can provide for optimal anatomical interfacing with the LGN in that hemisphere (e.g., for yielding an optimal phosphene pattern). Additionally, or alternatively, an MRI image of the brain can be acquired and analyzed to (a) delineate borders of the LGN, (b) determine a penetration distance from the bushing to the LGN, and / or (c) determine a trajectory of the center channel of the bushing with respect to the desired (or planned) trajectory determined at block 1302.

[0161] At block 1308, the method 1300 continues by determining a configuration for a personalized grid insert that can be used to advance one or more electrodes of an electrode array along the desired (or planned) trajectory and toward the target site / location within the organ or other tissue. Determining the configuration for the personalized grid insert can include determining a location and angular orientation of one or more channels formed in the grid insert. The location and angular orientation of each channel can be based at least in part on the position of the bushing determined at block 1306 and the location of the target site / location within the organ or other tissue.

[0162] For example, the location and / or orientation of each channel within the grid insert can be determined based at least in part on the locations of various neural sites within an LGN region that are targets for recording and / or stimulation, the desired (or planned) trajectory determined at block 1302, the position of the bushing determined at block 1306, and / or the orientation of the center channel of the bushing determined at block 1306. More specifically, a channel can be positioned at a location in the grid insert and be oriented to facilitate directing one or more electrodes (i) to and / or proximate one or more target neural sites within the LGN region and (ii) along a desired trajectory. As a specific example, in the event the position of the bushing and the orientation of the center channel of the bushing determined at block 1306 align with the planned site for the burr hole and the desired trajectory, respectively, that were determined at block 1302 (e.g., within a threshold margin of error), channels formed in a personalized grid insert can be coaxially aligned with an axis / orientation of the center channel of the bushing when the grid insert is inserted within the bushing at block 1312 below.-M-

[0163] On the other hand, in the event the position of the bushing and / or the orientation of the center channel of the bushing determined at block 1306 do not align with the planned site for the burr hole and / or the desired trajectory, respectively, that were determined at block 1302, channels formed in a personalized grid insert can include axes that are offset at an angle from the axis / orientation of the center channel of the bushing when the grid insert is inserted within the bushing at block 1312 below. The offset angle can be configured to compensate for misalignment between (a) the position of the bushing and / or the axis / orientation of the center channel of the bushing and (b) the desired trajectory, such that one or more electrodes inserted into the brain or other tissue via the channels in the grid insert are advanced along the desired the trajectory determined at block 1302. In other words, one or more channels in a grid insert can be formed at an angle with respect to an axis of the grid insert such that when the grid insert is inserted coaxially into the bushing, the channels in the grid insert are disposed at a non-zero longitudinal angle from the longitudinal axis of the bushing. The offset is expected to facilitate accurate deployment of one or more electrodes to a target site within an organ or other tissue, and along a desired trajectory. Thus, the angular offset allows for an adjustment in trajectory of the electrodes inserted into the cranial cavity via the bushing without removal and reinsertion of the bushing itself.

[0164] In some embodiments, the system includes a controller comprising processing circuitry and a memory having instructions stored thereon that, when executed by the processing circuitry, cause the processing circuitry to determine, based on imaging (e.g., MRI, CT, etc.), a required adjustment to the trajectory of the center channel of the bushing and the corresponding configuration of channels in the grid insert (e.g., the position, orientation, etc. of the channels). For example, the controller can determine that the actual trajectory of an electrode inserted through the center channel of the bushing will be different from the desired (or pre-planned) trajectory, and can determine a required adjustment based on the difference. In some embodiments, the controller can then output the adjustment and / or the required configuration for the channels in the grid insert to a system for fabricating the grid insert. In these and other embodiments, the controller can determine that the actual trajectory of an electrode inserted through the center channel of the bushing may not result in a desired treatment outcome (e.g., a desired stimulation or recording). In response, the controller can determine a new (or updated) trajectory for the electrode to position the electrode at a target site to achieve the desired treatment outcome.

[0165] At block 1310, the method 1300 continues by forming the personalized grid insert and / or threading one or more electrode shanks into one or more channels of the grid insert. In some embodiments, electrode shanks may be threaded and preassembled within channels of the grid insert before the grid insert is inserted within the bushing at block 1312 below. In such embodiments, the electrode shanks can be inserted into one or more channels of the grid insert to a depth that confines distal tips of the electrode shanks within the gird insert (e.g., to protect the electrodes from damage during handling and / or insertion of the grid insert within the bushing at block 1312 below). Additionally, or alternatively, electrode shanks may be threaded into and / or through one or more channels in the grid insert after the grid insert is inserted into the center channel of the bushing at block 1312 below.

[0166] The electrode shanks can be threaded into the one or more channels individually or in electrode array groups. In some embodiments, an electrode shank may be threaded into and / or through a channel in the grid insert using a stylet, such as by pushing the electrode shank into and / or through the hole using the stylet, rotating or screwing the stylet, or using another suitable method. In these and other embodiments, an electrode shank and / or an electrode array group can be threaded into and / or through a channel in the grid insert using a rod assembly, a slotted cannula, an introducer, and / or an obturator, as discussed above. Optionally, once an electrode shank is threaded into and / or through a channel in the grid insert, the shank can be removably anchored to the grid insert with dissolvable PEG or another suitable material / adhesive.

[0167] At block 1312, the method 1300 continues by positioning the personalized grid insert to a desired depth within the center channel of the bushing. For example, as shown in FIGS. 15B and 15C, the grid insert can be inserted within the bushing using a lead screw and one or more guide rods (e.g., tungsten rods) that are releasably secured to the bushing. As discussed above, the grid insert can include alignment / mating apertures that can interface (a) with the lead screw and guide rods to guide the grid insert into the center channel of the bushing and / or (b) with corresponding mating apertures / recesses in the bushing when a body portion of the grid insert is positioned within the center channel of the bushing.

[0168] At block 1314, the method 1300 continues by guiding or positioning electrodes of an electrode array to target sites / locations within the organ or other tissue. Guiding or positioning electrodes to the target sites / locations can include advancing the electrodes distally through channels in the grid insert, through the center channel of the bushing, and along the desiredtrajectory. Electrodes can be advanced distally to any desired depth (e.g., about 5 cm to about 10 cm for deep brain targets or less than 5 cm for shallower targets).

[0169] In some embodiments, guiding or positioning electrodes to target sites / locations can include advancing the electrodes distally manually or using a microdrive system, such as the microdrive system described above with reference to FIG. 10. The microdrive system can be manually operated, or can be fully or partially automatic (e.g., using a controller and / or a motor). As a specific example, the system can include a controller comprising processing circuitry and a memory having instructions stored thereon that, when executed by the processing circuitry, cause the processing circuitry to (a) determine appropriate insertion depths for one or more electrodes and / or (b) track and / or control depths of the electrodes during insertion via the microdrive system. The microdrive system can facilitate performing one or more the following actions (alone or in combination): rotating an electrode, electrode shank, and / or electrode array group; inserting the electrode, electrode shank, and / or electrode array group distally; or retracting the electrode, electrode shank, and / or electrode array group proximally.

[0170] In some embodiments, guiding or positioning electrodes of an electrode array to target sites / locations within the organ or other tissue can include monitoring position / movement of the electrodes using one or more visualization techniques, such as MRI, X-Ray, CT scan, or the like. In some embodiments, one or more of the electrodes, electrode shanks, and / or electrode array groups can include depth markers to provide an indication of the depth of one or more electrode during the insertion process.

[0171] In these and other embodiments, the system can include a controller comprising processing circuitry and a memory having instructions stored thereon that, when executed by the processing circuitry, cause the processing circuitry to monitor positions and / or trajectories of one or more of the electrodes during the insertion process (e.g., in comparison to the desired or updated trajectory described above), determine appropriate trajectory adjustments (if any) for the one or more electrodes, and / or provide corresponding information (e.g., a required reconfiguration of the grid insert, such as use of a new grid insert with different channel locations and / or orientation; and / or adjustments to electrode depths) to a user / operator. The corresponding information can be provided to the user / operator via a display, visual indicators, audio feedback, tactile feedback, etc. In turn, the user / operator can make corresponding adjustments, such as removal of the grid insert from within the bushing, installation of a newlyconfigured / reconfigured grid insert within the bushing, and / or adjustment to insertion depths of one or more electrodes (e.g., via the microdrive system).

[0172] Additionally, or alternatively, guiding or positioning electrodes of an electrode array to target sites / locations within the organ or other tissue can include coupling one or more measurement devices to muscles or other tissues of the subject that are stimulated by target neurons. Additionally, or alternatively, guiding or positioning electrodes of an electrode array to target sites / locations within the organ or other tissue can include coupling (a) a unit that collects input / feedback from the subject or a clinician to (b) a control unit or a microdrive system. The measurement devices and / or the input / feedback from a subject / clinician can be used to monitor responses of target muscles or other tissues to stimulation or recording supplied by implanted electrode(s). For example, during the insertion process, one or more of the electrodes can be used to record and / or apply stimulation (e.g., at the direction of a system controller or pulse generator). Target muscle / tissue responses to the recording / stimulation can be used to identify target neurons and facilitate accurate positioning of the electrode(s) within the organ or other tissue.

[0173] In these and other embodiments, guiding or positioning electrodes of an electrode array to target sites / locations within the organ or other tissue can include recording using one or more of the electrodes during the insertion process. Characteristics and other information recorded by the one or more electrodes can be used to facilitate accurate placement of the electrodes at a target site within the organ or other tissue. For example, recordings captured using one or more of electrodes during prior insertion processes (e.g., in the same subject or in one or more different subjects) can be paired with subsequent patient feedback regarding the quality of phosphenes evoked by those electrodes or by one or more surrounding electrodes. The patient feedback can indicate whether a phosphene is perceptually distinct, beneficial, of poor quality; whether a phosphene is of an unexpected or changed color or hue; etc. Such pairings of patient feedback with electrode impedance values and recordings captured by the electrodes during the insertion processes (or later after implantation) can help to characterize electrode and / or device health, integrity of the patient’s LGN neurons or other target cells, and can help to identify characteristics / other information in the recordings that indicate optimal placement of the electrodes (e.g., for evoking repeatable and reliable, and spatiotemporally distinct phosphenes with high signal-to-noise ratio). This knowledge can be leveraged in subsequent insertion procedures to guide the placement of electrodes within an organ or other tissue. For example, while implanting electrodes at block 1314 of the method 1300, the recordings of one or more electrodes captured during the insertion process can be monitored for the characteristics / otherinformation that indicate optimal placement of the electrodes (or of surrounding electrodes) for evoking phosphenes.

[0174] After inserting the electrodes to target sites within the brain or other organ / tissue, PEG or another dissolvable material / adhesive that holds the electrodes / electrode shanks to corresponding stylets can dissolve within a predefined time period (e.g., about ten minutes). Tn embodiments in which PEG or another dissolvable material / adhesive is used to releasably secure electrode shanks to the grid insert, the PEG or the other dissolvable material / adhesive on the grid insert can dissolve a period of time after the grid insert and / or the electrode shanks have been inserted into the subject by a predetermined depth, such as by exposure to temperatures / humidity internal the subject and / or by application of sterile normal saline (e.g., to portions of the grid insert and / or PEG or other material located outside of the subject). After the PEG or other material has dissolved, stylets, insertion rods, ganging members, and / or other insertion components can be withdrawn manually and / or using the microdrive system while leaving the electrodes in place at the target sites / location within the organ or other tissue. Optionally, sterile USP Class VI adhesive can be applied to the top of each channel in the grid insert to (i) prevent slippage of an electrode or electrode shank out of the grid insert and / or (ii) protect the electrodes / electrode shanks. As shown in FIG. 15D, after the stylets, insertion rods, ganging members, and / or other insertion components have been removed, the guide rods and the lead screw can be removed from the bushing. As shown in the illustrated embodiment, an electrode array can thereby be introduced and positioned at target sites within the organ or other tissue.

[0175] Although the blocks 1302-1314 of the method 1300 are described and illustrated in a particular order, the method 1300 of FIG. 13 is not so limited. In other embodiments, all or a subset of one or more of the blocks 1302-1314 of the method 1300 can be performed in a different order. In these and other embodiments, all or a subset of any of the blocks 1302-1314 can be performed before, during, and / or after all or a subset of any of the other blocks 1302- 1314. For example, the grid insert can be inserted into the bushing at block 1312 before electrode shanks are loaded / threaded into and / or through channels in the grid insert at block 1310. Furthermore, a person skilled in the art will readily appreciate that the method 1300 can be altered and still remain within these and other embodiments of the present technology. For example, all or a subset of one or more of the blocks 1302-1314 can be omitted and / or repeated in some embodiments.

[0176] As another example, the method 1300 can include one or more additional steps than shown in FIG. 13. As a specific example, referring to FIG. 15E, after an electrode array has been inserted to target sites within an organ or other tissue (or after multiple electrode arrays have been inserted to target sites within one or more organs or tissues), the method 1300 can include coupling electrical leads extending from electrodes of the electrode array(s) to a controller or pulse generator that is usable to control the electrodes individually and / or collectively in one or more groups. As discussed above, all or a subset of the electrodes can be used to record and / or apply electrical stimulation to surrounding tissue.

[0177] As another specific example, the method 1300 can include one or more mapping steps for creating a phosphene look-up table. As discussed above, a phosphene look-up table can be a list indexed by phosphene identifier number that is used by stimulation pattern creation software to activate desired phosphenes to create a desired percept. Creation of the phosphene look-up table can include (a) using a controller / pulse stimulator to apply, via one or more electrodes of the implanted electrode array, stimulation to tissue surrounding the one or more electrodes, and (b) collecting patient feedback regarding characteristics (e.g., location, size, shape, color (intensity, hue, etc.), quality, etc.) of evoked phosphenes. In the event the subject has residual vision, a custom array of optical phosphene simulants can be presented in their remaining visual field, and the subject can be asked to choose the closest match to an evoked phosphene via pointing or touch interface. The resulting matched characteristics can be stored in the phosphene look-up-table.

[0178] As discussed above, the LGN receives information directly from the retinal ganglion cells of the retina and projects mainly to the primary visual cortex. As such, the LGN holds promise as a target for electrical stimulation for artificial visual percepts because LGN microstimulation produces predictable visual percepts of patches of perceived light called phosphenes. Therefore, a visual prosthesis based on LGN stimulation could be helpful to restore sight to those who have become blind due to any source of impaired retinogeniculate transmission. This includes blindness in one or both eyes because of trauma to the eye (including enucleation and loss of the globe and retinal detachment) and diseases such as glaucoma, macular degeneration, retinitis pigmentosa, and diabetic retinopathy. Electrode arrays of the present technology can therefore be implanted in the LGN of each hemisphere of a subject’s brain. Electrodes of the electrode arrays can be stimulated in desired spatiotemporal patterns to produce phosphene vision, a new modality inspired by normal visual function. The stimulation patterns are created by transforming information about the subject’s environment (e.g., obtained from animaging device, such as an imaging device worn by the subject as part of a complete visual prosthesis system).

[0179] Thus far, LGN stimulation for vision restoration has not been attempted in humans. The chief reason for this is the LGN’s anatomical location deep within the brain and its relatively small size (the LGN cellular volume fits within a 1 cm cube), limiting the number of electrodes that can be inserted in the LGN and thus limited visual resolution. The present technology overcomes these issues by providing a high-density 3D electrode array and an accurate and precise insertion method to safely implant hundreds or thousands of electrodes in the LGN at distributed retinotopic locations. The electrode arrays provide for multipolar stimulation to maximize the locality of stimulation and customizability of stimulation. There is no existing electrode array or implantation system known to the inventors that can achieve one or more of the following provided by electrode arrays of the present technology: density and quantity of electrodes, multipolar stimulation deep in the brain, accuracy and precision of implantation, distributed targeting of the retinotopy with minimal phosphene overlap, and / or a compact, chronically implantable package supporting an elegant and efficient implantation procedure.Surgical Kits

[0180] In some embodiments, prosthetic systems and / or associated insertion devices of the present technology can be provided as part of a surgical kit. The kit can comprise components and / or material useful for using the prosthetic systems and / or performing one or more of the associated methods described herein. For example, the kit can include instructional material that describes, for instance, the method of using the bushing, the grid insert, and / or the electrode(s) (including one or more bushings, one or more grid inserts, and / or one or more electrodes) of the present technology. The kit may additionally, or alternatively, comprise components and materials useful for performing the methods of the disclosure. For example, the kit can comprise a bushing, a grid insert, a fiducial marker, electrode connectors, and / or electrode(s) (e.g., electrode shanks, electrode array group arrangements, pulse generators, glasses, etc.). In these and other embodiments, the kit may further comprise associated software and electronic equipment. The software and electronic equipment may be presented in a compact form for portable use.

[0181] In some embodiments, the kit comprises instructional material. Instructional material may include a publication, a recording, a diagram, or any other medium of expression which can be used to communicate the usefulness of the device described herein. Theinstructional material of the kit of the disclosure may, for example, be affixed to a package which contains one or more instruments which may be necessary for the desired procedure. Alternatively, the instructional material may be shipped separately from the package, or may be accessible electronically via a communications network, such as the Internet.

[0182] In one embodiment, the kit can be configured for portable use. To facilitate portable use, a kit of the present disclosure may further include a razor or clipper for removing hair from a subject, a ruler or tape measure for measuring the location of a site for incision, a surgical marker or other implement for marking the site of incision, skin preparation material (i.e., antiseptic, alcohol pads) to clean the site of incision, a scalpel to perform the incision, a drilling instrument to perforate any bone, and any additional surgical and medical elements that may be useful for such an operation, such as surgical tape, gauze, bandages, surgical thread and needle, and the like.Associated Computing and Processing Systems

[0183] In some embodiments, the devices of the present invention may operate in conjunction with a computer platform system, such as a local or remote executable software platform, or as a hosted internet or network program or portal. In certain embodiments, portions of the system may be computer operated, or in other embodiments, the entire system may be computer operated. As contemplated herein, any computing device as would be understood by those skilled in the art may be used with the system, including desktop or mobile devices, laptops, desktops, tablets, smartphones or other wireless digital / cellular phones, televisions or other thin client devices as would be understood by those skilled in the art.

[0184] The computer platform can be configured to record received emissions signals, and subsequently interpret the emissions. For example, the computer platform may be configured to interpret the emissions as images and subsequently transmit the images to a digital display. The computer platform may further perform automated calculations based on the received emissions to output data such as density, distance, temperature, composition, imaging, and the like, depending on the type of emissions received. The computer platform may further provide a means to communicate the received emissions and data outputs, such as by projecting one or more static and moving images on a screen, emitting one or more auditory signals, presenting one or more digital readouts, providing one or more light indicators, providing one or more tactile responses (such as vibrations), and the like. In some embodiments, the computer platform communicates received emissions signals and data outputs in real time, such that an operatormay adjust the use of the device in response to the real time communication. For example, in response to a stronger received emission, the computer platform may output a more intense light indicator, a louder auditory signal, or a more vigorous tactile response to an operator, such that the operator may adjust the device to receive a stronger signal or the operator may partially lock the device in a position that registers the strongest signal. In a further example, the computer platform may display image overlays to represent an inserted medical device in relation to a displayed ultrasound image or volume rendering (3D reconstruction) on screen.

[0185] The computer operable component(s) may reside entirely on a single computing device, or may reside on a central server and run on any number of end-user devices via a communications network. The computing devices may include at least one processor, standard input and output devices, as well as all hardware and software typically found on computing devices for storing data and running programs, and for sending and receiving data over a network, if needed. If a central server is used, it may be one server or, more preferably, a combination of scalable servers, providing functionality as a network mainframe server, a web server, a mail server and central database server, all maintained and managed by an administrator or operator of the system. The computing device(s) may also be connected directly or via a network to remote databases, such as for additional storage backup, and to allow for the communication of files, email, software, and any other data formats between two or more computing devices. There are no limitations to the number, type or connectivity of the databases utilized by the system of the present invention. The communications network can be a wide area network and may be any suitable networked system understood by those having ordinary skill in the art, such as, for example, an open, wide area network (e.g., the internet), an electronic network, an optical network, a wireless network, a physically secure network or virtual private network, and any combinations thereof. The communications network may also include any intermediate nodes, such as gateways, routers, bridges, internet service provider networks, public- switched telephone networks, proxy servers, firewalls, and the like, such that the communications network may be suitable for the transmission of information items and other data throughout the system.

[0186] The software may also include standard reporting mechanisms, such as generating a printable results report, or an electronic results report that can be transmitted to any communicatively connected computing device, such as a generated email message or file attachment. Likewise, particular results of the aforementioned system can trigger an alert signal, such as the generation of an alert email, text or phone call, to alert a manager, expert, researcher,or other professional of the particular results. Further embodiments of such mechanisms are described elsewhere herein or may include standard systems understood by those skilled in the art. As stated previously, the skull mounted bushing is robust, accurate, and provides a seamless way to provide stereotactic guidance, placement and fixation for the operation of instruments or devices. Additionally, the skull mounted bushing described herein has a slim profile, which provisions multiple bushings to be inserted into the skull within close proximity of one another.

[0187] FIG. 16 illustrates a processing system 1690 configured in accordance with various embodiments of the present technology, and illustrates examples of hardware found in a controller or computing system (such as a personal computer, e.g., a laptop or desktop computer, which can embody a workstation according to this disclosure) for implementing and / or executing the processes, algorithms, and / or methods described in this disclosure. The processing system 1690 can include one or more sub-processing systems that can be implemented in one or more of the components shown in FIG. 16. One or more of the sub-processing systems can be provided to collectively and / or cooperatively implement the processes and algorithms discussed herein.

[0188] As shown in FIG. 16, the processing system 1690 can be implemented using a microprocessor or its equivalent, such as a central processing unit (CPU) 1691 and / or at least one application specific processor ASP (not shown). The microprocessor is a circuit that utilizes a computer readable storage medium, such as a memory circuit 1692 (e.g., ROM, EPROM, EEPROM, flash memory, static memory, DRAM, SDRAM, and their equivalents), configured to control the microprocessor to perform and / or control the processes and systems of this disclosure. Other storage mediums can be controlled via a controller, such as a disk controller 1693, which can control a hard disk drive or optical disk drive.

[0189] The microprocessor or aspects thereof, in alternate implementations, can include or exclusively include a logic device for augmenting or fully implementing this disclosure. Such a logic device includes, but is not limited to, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a generic-array of logic (GAL), and their equivalents. The microprocessor can be a separate device or a single processing mechanism. Further, this disclosure can benefit from parallel processing capabilities of a multi-cored CPU.

[0190] In another aspect, results of processing in accordance with this disclosure can be displayed via a display controller 1694 to a monitor 1695. The display controller 1694 preferably includes at least one graphic processing unit, which can be provided by a plurality of graphics processing cores, for improved computational efficiency. Additionally, an I / O (input / output)interface 1696 is provided for inputting signals and / or data from microphones, speakers, cameras, a mouse, a keyboard, a touch-based display or pad interface, etc., which can be connected to the I / O interface 1696 as a peripheral 1697. For example, a keyboard or a pointing device for controlling parameters of the various processes and algorithms of this disclosure can be connected to the I / O interface 1696 to provide additional functionality and configuration options, or control display characteristics. Moreover, the monitor 1695 can be provided with a touch-sensitive interface for providing a command / instruction interface.

[0191] The above- noted components can be coupled to a network 1698, such as the Internet or a local intranet, via a network interface 1699 for the transmission or reception of data, including controllable parameters. A central BUS 1689 is provided to connect the above hardware components together and provides at least one path for digital communication there between.

[0192] Additionally, or alternatively, the system 1690 can include an audio processor 1688. In these and other embodiments, the I / O interface 1696 of the system 1690 can be configured to interface with one or more actuators 1687, imaging systems 1685 (e.g., MRI imaging systems, CT imaging systems, ultrasound imaging systems, etc.), and / or one or more electrodes 1686 (e.g., of an electrode array of the present technology.C. Examples

[0193] Several aspects of the present technology are set forth in the following examples. Although several aspects of the present technology are set forth in examples directed to systems and methods, these aspects of the present technology can similarly be set forth in examples directed to methods and systems, respectively, in other embodiments. Additionally, these aspects of the present technology may be set forth in examples directed to devices and / or (e.g., non- transitory) computer-readable media in other embodiments.1. An electrode shank, comprising: a plurality of electrodes; and a body extending between a proximal end region and a distal end region opposite the proximal end region, wherein the body includes — a plurality of non-conductive layers arranged in a stack, and a plurality of conductive traces formed on each of the plurality of non-conductive layers,wherein: the plurality of electrodes are disposed on the body, and each of the plurality of conductive traces extends from the proximal end region to a corresponding one of the plurality of electrodes.2. The electrode shank of example 1 , wherein a first set of the plurality of electrodes are disposed on a first side of the body.3. The electrode shank of example 1 or example 2, wherein the plurality of electrodes includes a first set of electrodes and a second set of electrodes different from the first set, and wherein the electrodes of the second set are disposed on a side of the body opposite the electrodes of the first set.4. The electrode shank of any of examples 1-3, wherein the electrode shank further comprises a conical tip portion.5. The electrode shank of any of examples 1-4, further comprising an aperture within the distal end region and configured to receive a distal end portion of a stylet.6. The electrode shank of any of examples 1-5, further comprising an insulative cover layer different from the plurality of non-conductive layers, wherein the plurality of electrodes are disposed in or on the insulative cover layer.7. The electrode shank of example 6, wherein the insulative cover layer is a first insulative cover layer that is disposed on a first side of the body, and wherein the electrode shank further comprises a second insulative cover layer separate from the plurality of non-conductive layer and disposed on a second side of the body opposite the first side.8. The electrode shank of any of examples 1-7, wherein each of the plurality of conductive traces includes (a) an elongated portion extending between the proximal end region and the distal end region of the body, and (b) a transverse extension electrically coupling the elongated portion to the corresponding one of the plurality of electrodes.9. The electrode shank of any of examples 1-8, wherein at least one non-conductive layer of the plurality of non-conductive layers is formed of a thin-film dielectric material.10. The electrode shank of example 9, wherein the thin-film dielectric material includes SU-8 photoresist, polyimide, mylar, or silicon.11. The electrode shank of any of examples 1-10, wherein at least one conductive trace of the plurality of conductive traces is formed of a thin-film conductive material.12. The electrode shank of any of examples 1-11, wherein each of the plurality of conductive traces are electrically isolated from one another such that each of the plurality of electrodes is independently addressable via a corresponding one of the plurality of conductive traces.13. An electrode array group arrangement, comprising: an electrode array group including a plurality of electrode shanks, each electrode shank of the plurality of electrode shanks having — a body extending between a proximal end portion and a distal end portion opposite the proximal end portion, wherein the body includes (i) a plurality of non-conductive layers and (ii) a plurality of conductive traces positioned between at least two non-conductive layers of the plurality of non-conductive layer, and a plurality of electrodes disposed on the distal end portion of the body, wherein each of the plurality of conductive traces extends from the proximal end portion to a corresponding one of the plurality of electrodes.14. The electrode array group arrangement of example 13, further comprising a rod assembly releasably secured to the plurality of electrode shanks of the electrode array group.15. The electrode array group arrangement of example 14, wherein the rod assembly includes a plurality of stylets, each releasably secured to a corresponding one of the plurality of electrode shanks.16. The electrode array group arrangement of example 15, wherein: the distal end portion of each electrode shank of the plurality of electrode shanks includes an aperture; each stylet of the plurality of stylets includes an elongated body portion and a distal end portion; the distal end portion of each of the plurality of stylets is positioned within the aperture of the corresponding one of the plurality of electrode shanks; and the elongated body portion of each of the plurality of stylets is releasably secured to the corresponding one of the plurality of electrode shanks via dissolvable polyethylene glycol (PEG).17. The electrode array group arrangement of example 15 or example 16, wherein the rod assembly further includes a ganging member ganging the plurality of stylets to one another.18. The electrode array group arrangement of any of examples 15-17, wherein the rod assembly further includes an insertion rod ganged to each of the plurality of stylets.19. The electrode array group arrangement of any of examples 13—18, further comprising an insertion disc including a plurality of apertures, wherein each electrode shank of the plurality of electrode shanks is at least partially positioned with a corresponding one of the plurality of apertures in the insertion disc.20. The electrode array group arrangement of any of examples 13-19, further comprising a flexible cable electrically coupled to an electrode shank of the plurality of electrode shanks, wherein the flexible cable includes a plurality of second traces (i) that are each coupled to a corresponding one of the plurality of conductive traces in the electrode shank and (ii) that each have a larger section modulus than the corresponding one of the plurality of conductive traces in the electrode shank.21. A visual prosthetic system, comprising: a pulse generator; andan electrode array implantable within a lateral geniculate nucleus (LGN) region of a brain, wherein the electrode array includes a plurality of electrode shanks, at least one of which includes — an elongated body extending between a proximal end region and a distal end region opposite the proximal end region, wherein the elongated body includes — a plurality of non-conductive layers arranged in a stack, and a plurality of conductive traces positioned between at least two of the plurality of non-conductive layers, and a plurality of electrodes disposed on the distal end region of the elongated body, wherein each of the plurality of conductive traces (i) extends from the proximal end region to a corresponding one of the plurality of electrodes and (ii) electrically couples the corresponding one of the plurality of electrodes to the pulse generator.22. The visual prosthetic system of example 21, wherein the plurality of conductive traces are electrically isolated from one another such that each of the plurality of electrodes is independently addressable by the pulse generator via a corresponding one of the plurality of conductive traces.23. The visual prosthetic system of example 21 or example 22, further comprising a cranial bushing and a grid insert positionable within a center channel of the cranial bushing, wherein the plurality of electrode shanks are implantable within the LGN region via one or more channels formed in the grid insert.24. The visual prosthetic system of any of examples 21-23, wherein: the electrode array is a first electrode array implantable within a first LGN region in a first hemisphere of the brain; and the visual prosthetic system further comprises a second electrode array separate from the first electrode array and implantable within a second LGN region in a second hemisphere of the brain different form the first hemisphere.25. The visual prosthetic system of any of examples 21-24, further comprising: an image sensor usable to acquire images of an external scene; and a controller configured to process the images and generate corresponding stimulation patterns, wherein the pulse generator is configured to control electrodes of the electrode array to apply stimulation to the LGN region in accordance with the stimulation patterns to evoke corresponding phosphene patterns.26. A method, comprising: positioning a grid insert within a subject, wherein the grid insert includes a channel or channels formed therein for directing one or more electrodes toward a target site in tissue of the subject in accordance with a planned trajectory; and implanting the one or more electrodes at the target site, wherein implanting the one or more electrodes includes (a) inserting the one or more electrodes through the channel in the grid insert and (b) advancing the one or more electrodes generally along the planned trajectory.27. The method of example 26, further comprising: inserting a bushing within the subject along the planned trajectory; determining an actual trajectory of an insertion channel of the bushing; and determining a location and an orientation for the channel or channels in the grid insert based at least in part on the actual trajectory, wherein positioning the grid insert within the subject includes positioning the grid insert within the central channel or bore of the bushing.28. The method of example 26 or example 27, wherein implanting the one or more electrodes at the target site includes distally advancing the one or more electrodes into the subject using a microdrive system including at least one guide rod and a lead screw.29. The method of any of examples 26-28, wherein the planned trajectory extends from a parietal-occipital junction in a brain of the subject to the target site within a lateral geniculate nucleus (LGN) of the brain.30. The method of any of examples 26-29, wherein the planned trajectory extends above and parallel to geniculocortical and corticogeniculate fibers in a brain of the subject that connect a lateral geniculate nucleus (LGN) of the brain to a visual cortex of the brain.31. The method of any of examples 26-30, wherein implanting the one or more electrodes at the target site includes recording using all or a subset of the one or more electrodes while advancing the one or more electrodes generally along the planned trajectory toward the target site.32. An electrode array, comprising: a plurality of electrode shanks, each of the electrode shanks including — an electrode body extending between a proximal end and a distal end, a plurality of planar, non-conductive layers included within the electrode body, and a plurality of conductive traces formed on each of the plurality of planar, non- conductive layers, each of the plurality of conductive traces extending from the proximal end and terminating at a contact formed on an upper surface, a lower surface, or a surface at the distal end of the electrode body and extending at least partway between the upper surface and the lower surface, wherein the electrode body comprises a plurality of contact pairs, each contact pair configurable to apply charge-balanced multipolar stimulation (e.g., of arbitrary polarity and / or spatial configuration) to surrounding tissue, and each contact pair comprising a first contact on the upper surface and a second contact on the lower surface, two or more adjacent contacts, two or more contacts at arbitrary locations on a same electrode shank or across multiple electrode shanks, or a single contact paired with a remote conductive body, such as a conductive metal package of an implanted pulse generator.33. The electrode array of example 32, wherein each of the plurality of electrode shanks further comprises a hole formed within a tip at the distal end.34. The electrode array of example 33, wherein each of the plurality of bipolar electrodes further comprises a stylet threaded through the hole and affixed to the body via dissolvable polyethylene glycol (PEG).35. The electrode array of any of examples 32-34, wherein the electrode body is configured for insertion within a lateral geniculate nucleus (LGN) region of a subject’s brain.36. The electrode array of example 35, wherein the plurality of contact pairs are configured to stimulate neurons within the LGN region and / or record signals from the same or different neurons within the LGN region.37. The electrode array of any of examples 32-36, wherein the plurality of contact pairs are configured to evoke a desired (e.g., retinocentric) phosphene pattern within visual space.38. A method for simultaneous insertion of a plurality of electrodes of an electrode array within a brain, the method comprising: inserting a cranial bushing in a skull along a first trajectory; determining, using a fiducial marker, (i) an actual trajectory of the cranial bushing or (ii) an optimal trajectory in a frame of reference of the cranial bushing, the optimal trajectory providing optimal targeting of the LGN; determining, based on the first trajectory, the actual trajectory, and / or the optimal trajectory, properties (e.g., position(s) and / or orientation(s)) of one or more holes formed in a grid insert (e.g., having an exterior that mates co-axially with the cranial bushing); forming the grid insert in accordance with the determined properties; and inserting, via the one or more holes and the grid insert, the plurality of the electrodes within the brain.39. The method of example 38, wherein the first trajectory is configured for insertion of the plurality of electrodes within a lateral geniculate nucleus (LGN) region of the brain.40. A visual prosthetic device, comprising: a controller; and an electrode array comprising a plurality of electrode shanks, each of the plurality of electrode shanks including — a plurality of contacts, each configured to record or apply stimulation to surrounding tissue, an electrode body extending between a proximal end and a distal end, the electrode body being configured for insertion within a lateral geniculate nucleus (LGN) region of a subject’s brain, a plurality of planar, non-conductive layers included within the electrode body, and a plurality of conductive traces formed on each of the plurality of planar, non- conductive layers, each of the plurality of conductive traces extending from the proximal end to a corresponding one of the plurality of contacts.41. The visual prosthetic device of example 40, wherein the controller is configured to cause the plurality of contacts to stimulate neurons within the LGN region to evoke a phosphene pattern, providing at the same time local detail (particularly in central vision) and global scene-level details, enabling artificial vision.42. The visual prosthetic device of example 40 or example 41, wherein the electrode array is a first electrode array, and wherein the visual prosthetic device further comprises a second electrode array including a second plurality of electrode shanks, each of the second plurality of electrode shanks having an electrode body configured for insertion within another lateral geniculate nucleus (LGN) region of the subject’s brain.43. A method of fabricating an electrode shank, the method comprising: forming a first insulation layer having at least one electrode disposed therein or thereon; and forming a first interconnect layer on or over the first insulation layer, the first interconnect layer comprising a first set of conductive traces, each conductive trace of the first set extending from a proximal end portion of the electrode shank to a corresponding one of the at least one electrode.44. The method of example 43 , wherein forming the first insulation layer includes (a) depositing a first conductive material and (b) defining the at least one electrode in the first conductive material using photolithography and etching.45. The method of example 43 , wherein forming the first insulation layer includes (a) depositing a photoresist material, (b) patterning the photoresist material, and (c) depositing a first conductive material corresponding to the at least one electrode over the patterned photoresist material.46. The method of any of examples 43-45, further comprising forming a second insulation layer on or over the first insulation layer, wherein forming the first interconnect layer includes forming the first interconnect layer on or over the second insulation layer such that the second insulation layer is positioned between the first insulation layer and the first interconnect layer.47. The method of example 46, wherein forming the second insulation layer includes depositing a thin- film dielectric material on or over the first insulation layer using spray coating.48. The method of any of examples 43-47, wherein forming the first interconnect layer includes forming elongated portions of conductive traces of the first set, wherein forming the elongated portions includes applying a coating of conductive material, coating the conductive material with a photoresist material, exposing the photoresist material to an image of a desired electrically conductive pattern, and removing unexposed portions of the photoresist material and corresponding underlying portions of the conductive material.49. The method of any of examples 43-48, wherein forming the first interconnect layer includes forming traverse portions of conductive traces of the first set, wherein forming the traverse portions includes forming the traverse portions using reactive ion etching.50. The method of any of examples 43-49, further comprising: forming a second interconnect layer on or over the first interconnect layer, the second interconnect layer comprising a second set of conductive traces; andforming another insulation layer on or over the second interconnect layer, the other insulation layer having one or more electrodes disposed therein or thereon, wherein each conductive trace of the second set extends from the proximal end portion of the electrode shank to a corresponding one of the one or more electrodes.51. The method of any one of examples 43-49, wherein: the first insulation layer and the first interconnect layer are part of a first-half portion of the electrode shank; the method further comprises forming a second-half portion of the electrode shank, wherein forming the second-half portion includes — forming another insulation layer having one or more electrodes disposed therein or thereon, and forming a second interconnect layer on or over the other insulation layer, the second interconnect layer comprising a second set of conductive traces, each conductive trace of the second set extending from a proximal end portion of the electrode shank to a corresponding one of the one or more electrodes; and the method further comprises affixing the second-half portion of the electrode shank to the first-half portion of the electrode shank.D. Conclusion

[0194] From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. The above detailed descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, although steps are presented in a given order above, alternative embodiments may perform steps in a different order. Furthermore, the various embodiments described herein may also be combined to provide further embodiments.

[0195] To the extent any material incorporated herein by reference conflicts with the present disclosure, the present disclosure controls. Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Furthermore, as used herein, the phrase “and / or” as in “A and / or B” refers to A alone, B alone, and both A and B. Additionally, the terms “comprising,” “including,” “having,” and “with” are used throughout to mean including at least the recited feature(s) such that any greater number of the same features and / or additional types of other features are not precluded. Moreover, as used herein, the phrases “based on,” “depends on,” “as a result of,” and “in response to” shall not be construed as a reference to a closed set of conditions. For example, a step that is described as “based on condition A” may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on” or the phrase “based at least partially on.”

[0196] Spatially relative terms, such as “beneath,” “below,” “over,” “under,” “above,” “upper,” “top,” “bottom,” “left,” “right,” “center,” “middle,” “forward,” “away,” and the like, are used herein for ease of description to describe one element or feature’s relationship relative to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures. For example, if a device or system in the figures is rotated or turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated ninety degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly. In addition, it will also be understood that when an element is referred to as being “between” two other elements, it can be the only element between the two other elements, or one or more intervening elements may also be present.

[0197] From the foregoing, it will also be appreciated that various modifications may be made without deviating from the disclosure or the technology. For example, one of ordinary skill in the art will understand that various components of the technology can be further divided intosubcomponents, or that various components and functions of the technology may be combined and integrated. In addition, certain aspects of the technology described in the context of particular embodiments may also be combined or eliminated in other embodiments. Furthermore, although advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

[0198] It will be understood that terms such as “same,” “equal,” “planar,” or “coplanar,” as used herein when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The terms “generally,” “substantially,” or “about” may be used herein to emphasize this meaning, unless the context or other statements clearly indicate otherwise. For example, items described as “substantially the same,” “substantially equal,” or “substantially planar,” may be exactly the same, equal, or planar, or may be the same, equal, or planar within acceptable variations that may occur, for example, due to manufacturing processes and / or tolerances. The terms “generally,” “substantially,” or “about” may be used to encompass this meaning, especially when such variations do not materially alter functionality.

Claims

CLAIMSWhat is claimed is:

1. An electrode shank, comprising: a plurality of electrodes; and a body extending between a proximal end region and a distal end region opposite the proximal end region, wherein the body includes — a plurality of non-conductive layers arranged in a stack, and a plurality of conductive traces formed on each of the plurality of non-conductive layers, wherein: the plurality of electrodes are disposed on the body, and each of the plurality of conductive traces extends from the proximal end region to a corresponding one of the plurality of electrodes.

2. The electrode shank of claim 1 , wherein a first set of the plurality of electrodes are disposed on a first side of the body.

3. The electrode shank of claim 1 , wherein the plurality of electrodes includes a first set of electrodes and a second set of electrodes different from the first set, and wherein the electrodes of the second set are disposed on a side of the body opposite the electrodes of the first set.

4. The electrode shank of claim 1 , wherein the electrode shank further comprises a conical tip portion.

5. The electrode shank of claim 1, further comprising an aperture within the distal end region and configured to receive a distal end portion of a stylet.

6. The electrode shank of claim 1, further comprising an insulative cover layer different from the plurality of non-conductive layers, wherein the plurality of electrodes are disposed in or on the insulative cover layer.

7. The electrode shank of claim 6, wherein the insulative cover layer is a first insulative cover layer that is disposed on a first side of the body, and wherein the electrode shank further comprises a second insulative cover layer separate from the plurality of non-conductive layer and disposed on a second side of the body opposite the first side.

8. The electrode shank of claim 1 , wherein each of the plurality of conductive traces includes (a) an elongated portion extending between the proximal end region and the distal end region of the body, and (b) a transverse extension electrically coupling the elongated portion to the corresponding one of the plurality of electrodes.

9. The electrode shank of claim 1 , wherein at least one non-conductive layer of the plurality of non-conductive layers is formed of a thin-film dielectric material.

10. The electrode shank of claim 9, wherein the thin-film dielectric material includes SU-8 photoresist, polyimide, mylar, or silicon.

11. The electrode shank of claim 1, wherein at least one conductive trace of the plurality of conductive traces is formed of a thin-film conductive material.

12. The electrode shank of claim 1 , wherein each of the plurality of conductive traces are electrically isolated from one another such that each of the plurality of electrodes is independently addressable via a corresponding one of the plurality of conductive traces.

13. An electrode array group arrangement, comprising: an electrode array group including a plurality of electrode shanks, each electrode shank of the plurality of electrode shanks having — a body extending between a proximal end portion and a distal end portion opposite the proximal end portion, wherein the body includes (i) a plurality of non-conductive layers and (ii) a plurality of conductive traces positioned between at least two non-conductive layers of the plurality of non-conductive layer, anda plurality of electrodes disposed on the distal end portion of the body, wherein each of the plurality of conductive traces extends from the proximal end portion to a corresponding one of the plurality of electrodes.

14. The electrode array group arrangement of claim 13, further comprising a rod assembly releasably secured to the plurality of electrode shanks of the electrode array group.

15. The electrode array group arrangement of claim 14, wherein the rod assembly includes a plurality of stylets, each releasably secured to a corresponding one of the plurality of electrode shanks.

16. The electrode array group arrangement of claim 15, wherein: the distal end portion of each electrode shank of the plurality of electrode shanks includes an aperture; each stylet of the plurality of stylets includes an elongated body portion and a distal end portion; the distal end portion of each of the plurality of stylets is positioned within the aperture of the corresponding one of the plurality of electrode shanks; and the elongated body portion of each of the plurality of stylets is releasably secured to the corresponding one of the plurality of electrode shanks via dissolvable polyethylene glycol (PEG).

17. The electrode array group arrangement of claim 15, wherein the rod assembly further includes a ganging member ganging the plurality of stylets to one another.

18. The electrode array group arrangement of claim 15, wherein the rod assembly further includes an insertion rod ganged to each of the plurality of stylets.

19. The electrode array group arrangement of claim 13, further comprising an insertion disc including a plurality of apertures, wherein each electrode shank of the plurality of electrode shanks is at least partially positioned with a corresponding one of the plurality of apertures in the insertion disc.

20. The electrode array group arrangement of claim 13, further comprising a flexible cable electrically coupled to an electrode shank of the plurality of electrode shanks, wherein the flexible cable includes a plurality of second traces (i) that are each coupled to a corresponding one of the plurality of conductive traces in the electrode shank and (ii) that each have a larger section modulus than the corresponding one of the plurality of conductive traces in the electrode shank.

21. A visual prosthetic system, comprising: a pulse generator; and an electrode array implantable within a lateral geniculate nucleus (LGN) region of a brain, wherein the electrode array includes a plurality of electrode shanks, at least one of which includes — an elongated body extending between a proximal end region and a distal end region opposite the proximal end region, wherein the elongated body includes — a plurality of non-conductive layers arranged in a stack, and a plurality of conductive traces positioned between at least two of the plurality of non-conductive layers, and a plurality of electrodes disposed on the distal end region of the elongated body, wherein each of the plurality of conductive traces (i) extends from the proximal end region to a corresponding one of the plurality of electrodes and (ii) electrically couples the corresponding one of the plurality of electrodes to the pulse generator.

22. The visual prosthetic system of claim 21 , wherein the plurality of conductive traces are electrically isolated from one another such that each of the plurality of electrodes is independently addressable by the pulse generator via a corresponding one of the plurality of conductive traces.

23. The visual prosthetic system of claim 21, further comprising a cranial bushing and a grid insert positionable within a center channel of the cranial bushing, wherein the plurality of electrode shanks are implantable within the LGN region via one or more channels formed in the grid insert.

24. The visual prosthetic system of claim 21 , wherein: the electrode array is a first electrode array implantable within a first LGN region in a first hemisphere of the brain; and the visual prosthetic system further comprises a second electrode array separate from the first electrode array and implantable within a second LGN region in a second hemisphere of the brain different form the first hemisphere.

25. The visual prosthetic system of claim 21 , further comprising: an image sensor usable to acquire images of an external scene; and a controller configured to process the images and generate corresponding stimulation patterns, wherein the pulse generator is configured to control electrodes of the electrode array to apply stimulation to the LGN region in accordance with the stimulation patterns to evoke corresponding phosphene patterns.

26. A method, comprising: positioning a grid insert within a subject, wherein the grid insert includes a channel formed therein for directing one or more electrodes toward a target site in tissue of the subject in accordance with a planned trajectory; and implanting the one or more electrodes at the target site, wherein implanting the one or more electrodes includes (a) inserting the one or more electrodes through the channel in the grid insert and (b) advancing the one or more electrodes generally along the planned trajectory.

27. The method of claim 26, further comprising: inserting a bushing within the subject along the planned trajectory; determining an actual trajectory of an insertion channel of the bushing; and determining a location and an orientation for the channel in the grid insert based at least in part on the actual trajectory, wherein positioning the grid insert within the subject includes positioning the grid insert within the channel of the bushing.

28. The method of claim 26, wherein implanting the one or more electrodes at the target site includes distally advancing the one or more electrodes into the subject using a microdrive system including at least one guide rod and a lead screw.

29. The method of claim 26, wherein the planned trajectory extends from a parietal- occipital junction in a brain of the subject to the target site within a lateral geniculate nucleus (LGN) of the brain.

30. The method of claim 26, wherein the planned trajectory extends above and parallel to geniculocortical and corticogeniculate fibers in a brain of the subject that connect a lateral geniculate nucleus (LGN) of the brain to a visual cortex of the brain.

31. The method of claim 26, wherein implanting the one or more electrodes at the target site includes recording using all or a subset of the one or more electrodes while advancing the one or more electrodes generally along the planned trajectory toward the target site.

32. An electrode array, comprising: a plurality of electrode shanks, each of the electrode shanks including — an electrode body extending between a proximal end and a distal end, a plurality of planar, non-conductive layers included within the electrode body, and a plurality of conductive traces formed on each of the plurality of planar, non- conductive layers, each of the plurality of conductive traces extending from the proximal end and terminating at a contact formed on an upper surface or a lower surface of the electrode body, wherein the electrode body comprises a plurality of contact pairs, each configurable to apply bipolar stimulation to surrounding tissue and each comprising a first contact on the upper surface and a second contact on the lower surface.

33. The electrode array of claim 32, wherein each of the plurality of electrode shanks further comprises a hole formed within a tip at the distal end.

34. The electrode array of claim 33, wherein each of the plurality of bipolar electrodes further comprises a stylet threaded through the hole and affixed the body via dissolvable polyethylene glycol (PEG).

35. The electrode array of claim 32, wherein the electrode body is configured for insertion within a lateral geniculate nucleus (LGN) region of a subject’s brain.

36. The electrode array of claim 35, wherein the plurality of contact pairs are configured to stimulate first neurons within the LGN region or record signals from second neurons within the LGN region.

37. The electrode array of claim 32, wherein the plurality of contact pairs are configured to evoke a desired retinocentric phosphene pattern within visual space.

38. A method for simultaneous insertion of a plurality of electrodes of an electrode array within a brain, the method comprising: inserting a cranial bushing in a skull along a first trajectory; determining, using a fiducial marker, an actual trajectory of the cranial bushing; determining, based on the first trajectory and the actual trajectory, properties of one or more holes formed in a grid insert; forming the grid insert in accordance with the determined properties; and inserting, via the one or more holes and the grid insert, the plurality of the electrodes within the brain.

39. The method of claim 38, wherein the first trajectory is configured for insertion of the plurality of electrodes within a lateral geniculate nucleus (LGN) region of the brain.

40. A visual prosthetic device, comprising: a controller; and an electrode array comprising a plurality of electrode shanks, each of the plurality of electrode shanks including — a plurality of contacts, each configured to record or apply stimulation to surrounding tissue,an electrode body extending between a proximal end and a distal end, the electrode body being configured for insertion within a lateral geniculate nucleus (LGN) region of a subject’s brain, a plurality of planar, non-conductive layers included within the electrode body, and a plurality of conductive traces formed on each of the plurality of planar, non- conductive layers, each of the plurality of conductive traces extending from the proximal end to a corresponding one of the plurality of contacts.

41. The visual prosthetic device of claim 40, wherein the controller is configured to cause the plurality of contacts to stimulate neurons within the LGN region to evoke a phosphene pattern.

42. The visual prosthetic device of claim 40, wherein the electrode array is a first electrode array, and wherein the visual prosthetic device further comprises a second electrode array including a second plurality of electrode shanks, each of the second plurality of electrode shanks having an electrode body configured for insertion within another lateral geniculate nucleus (LGN) region of the subject’s brain.

43. A method of fabricating an electrode shank, the method comprising: forming an insulation layer having at least one electrode disposed therein or thereon; and forming an interconnect layer on or over the insulation layer, the interconnect layer comprising a set of conductive traces, each conductive trace of the set extending from a proximal end portion of the electrode shank to a corresponding one of the at least one electrode.

44. The method of claim 43, wherein forming the insulation layer includes (a) depositing a conductive material and (b) defining the at least one electrode in the conductive material using photolithography and etching.

45. The method of claim 43, wherein forming the insulation layer includes (a) depositing a photoresist material, (b) patterning the photoresist material, and (c) depositing aconductive material corresponding to the at least one electrode over the patterned photoresist material.

46. The method of claim 43, wherein: the insulation layer is a first insulation layer; the method further comprises forming a second insulation layer on or over the first insulation layer; and forming the interconnect layer includes forming the interconnect layer on or over the second insulation layer such that the second insulation layer is positioned between the first insulation layer and the interconnect layer.

47. The method of claim 46, wherein forming the second insulation layer includes depositing a thin- film dielectric material on or over the first insulation layer using spray coating.

48. The method of claim 43, wherein forming the interconnect layer includes forming elongated portions of conductive traces of the set, wherein forming the elongated portions includes applying a coating of conductive material, coating the conductive material with a photoresist material, exposing the photoresist material to an image of a desired electrically conductive pattern, and removing unexposed portions of the photoresist material and corresponding underlying portions of the conductive material.

49. The method of claim 43, wherein forming the interconnect layer includes forming traverse portions of conductive traces of the set, wherein forming the traverse portions includes forming the traverse portions using reactive ion etching.

50. The method of claim 43, wherein: the interconnect layer is a first interconnect layer, the insulation layer is a first insulation layer, and the set of conductive traces is a first set of conductive traces; the method further comprises — forming a second interconnect layer on or over the first interconnect layer, the second interconnect layer comprising a second set of conductive traces; andforming a second insulation layer on or over the second interconnect layer, the second insulation layer having one or more electrodes disposed therein or thereon, wherein each conductive trace of the second set extends from the proximal end portion of the electrode shank to a corresponding one of the one or more electrodes.

51. The method of claim 43 , wherein: the interconnect layer is a first interconnect layer, the insulation layer is a first insulation layer, and the set of conductive traces is a first set of conductive traces; the first insulation layer and the first interconnect layer are part of a first-half portion of the electrode shank; the method further comprises forming a second-half portion of the electrode shank, wherein forming the second-half portion includes — forming a second insulation layer having one or more electrodes disposed therein or thereon, and forming a second interconnect layer on or over the second insulation layer, the second interconnect layer comprising a second set of conductive traces, each conductive trace of the second set extending from a proximal end portion of the electrode shank to a corresponding one of the one or more electrodes; and the method further comprises affixing the second-half portion of the electrode shank to the first-half portion of the electrode shank.

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