Parameter selection in focused ultrasound neuromodulation

Abstract

Disclosed are devices, systems, and methods for ultrasonically stimulating brain tissue using operating parameters associated with a. target region of a brain. The operating parameters can be determined, for example, by combined ultrasonic stimulation and photometry devices and methods. The operating parameters can include pulse repetition frequency, temporal compression, and intensity. Using selected operating parameters, ultrasound stimulation of the target region of the brain can excite or inhibit brain cell activity.

Description

STANJ.009WO PATENT PARAMETER SELECTION IN FOCUSED ULTRASOUND NEUROMODULATION CROSS REFERENCE TO PRIORITY APPLICATION

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 593,891, filed October 27, 2023 and titled “PARAMETER OPTIMIZATION IN FOCUSED ULTRASOUND NEUROMODULATION,” the disclosure of which is hereby incorporated by reference in its entirely. FEDERAL SUPPORT STATEMENT

[0002] This invention was made with Government support under contract DA055056 awarded by the National Institutes of Health. The Government has certain rights in the invention. BACKGROUND Technical Field

[0003] The disclosed technology relates to ultrasound and photometry including related devices, systems, and methods. Description of the Related Art

[0004] Using ultrasound to non-invasively modulate behavior of a brain is a growing area of research. Studies have demonstrated that ultrasound can alter neuronal and brain-network activity. Neuromodulation using ultrasound has great potential to non- invasively treat a wide array of neurological disorders, including epilepsy, essential tremor, depression, and sleep disorders. However, detecting neuronal activity and / or an impact of ultrasound on specific brain cells has presented technical challenges. Accordingly, improved devices, systems, and methods for detecting responses to and / or determining parameters for ultrasound delivered to brain cells would be desirable.SUMMARY

[0005] The innovations described in the claims each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the claims, some prominent features of this disclosure will now be briefly described.

[0006] One aspect of the disclosed technology is a method of stimulating a region of a brain of a subject, the method including: accessing parameter data stored in a hardware processor, the parameter data associated with a plurality of parameter sweeps, the parameter data comprising data associated with ultrasonic pulse repetition frequency (PRF), ultrasonic temporal compression, and ultrasonic intensity for a target region of the brain; setting parameters of an ultrasound transducer for the target region of the brain, based at least in part on the parameter data; and applying ultrasound energy to the target region of a brain using an ultrasonic transducer to excite cells in the target region of the brain, the ultrasound energy exhibiting the set parameters, wherein a temperature of the target region of the brain is reduced from the applying.

[0007] The applied PRF can be a frequency below 10 hertz (Hz).

[0008] The applied compression is a compression can range from 5% to 15% duty cycle (D.C.).

[0009] The setting can be based at least in part on a target cell type.

[0010] The method can include generating the parameter data. In such examples, generating the parameter data may include conducting the parameter sweeps in the PRF parameter space, in the compression parameter space, and in the intensity parameter space. Additionally or alternatively, generating the parameter data may include measuring a plurality of GCaMP responses to ultrasonic stimulation. Measuring the plurality of GCaMP responses may be conducted using a fiber photometer.

[0011] Another aspect of the disclosed technology is a system for stimulating a region of a brain of a subject, the system including: an ultrasound transducer can transmit ultrasonic energy to the region of the brain of the subject; and a hardware processor in communication with the ultrasound transducer, the hardware processor can: set operating parameters of the ultrasound transducer based at least in part on a target region of the brain, wherein the parameters include pulse repetition frequency (PRF), temporal compression, and intensity, and cause the ultrasound transducer to operate based on the set operating parameters.

[0012] In some aspects, the techniques described herein relate to a system, wherein the hardware processor can access a non-volatile memory, and wherein the non-volatile memory can store parameter sweep curves for each of a PRF parameter space, a temporal compression parameter space, and an intensity parameter space, and wherein the hardware processor can set the operating parameters of the ultrasound transducer based at least in part on the stored parameter sweep curves.

[0013] The hardware processor can cause the transducer to operate at a PRF of between 10 and 30 Hz. The hardware processor can set the operating parameters of the ultrasound transducer based at least in part on a target cell type. The hardware processor can set the operating parameters of the ultrasound transducer to excite a target cell type. The hardware processor can set the operating parameters of the ultrasound transducer to inhibit activity of a target cell type. The ultrasound transducer is noninvasive.

[0014] Another aspect of the disclosed technology is a method of stimulating a region of a brain of a subject, the method including: setting parameters of an ultrasound transducer based at least in part on a target region of the brain, where the parameters include pulse repetition frequency (PRF), temporal compression, and intensity; and applying ultrasound energy to the target region of a brain using an ultrasonic transducer, the ultrasound energy exhibiting the set parameters. The applied PRF may be a frequency ranging between 10 and 30 Hz.

[0015] The applied compression may be a compression ranging from 5% to 15% duty cycle (D.C.).

[0016] The setting may be based at least in part on a target cell type.

[0017] The setting may be based at least in part on a plurality of parameter sweeps of a PRF parameter space, a temporal parameter space, and an intensity parameter space in a control subject.

[0018] Another aspect of the disclosed technology is a method of determining ultrasonic stimulation parameters for a region of a brain using a system that can combine ultrasound stimulation and photometry, the method including: stimulating, using an ultrasonic transducer, the region of the brain while a tip of an optical delivery element is positioned at the region of the brain, wherein the stimulating includes conducting a parameter sweep in a pulse repetition frequency (PRF) parameter space, a temporal compression parameter space, and anintensity parameter space; transmitting, while ultrasound stimulation is being applied to the region of the brain, light from a light source to the region of the brain via the optical delivery element; detecting, with a detector, a plurality of responses of the brain to the ultrasonic stimulation; and storing, in non-transitory memory, parameter data associated with the plurality of responses.

[0019] The method may additionally include selecting, based at least in part on the parameter data plurality of responses, a PRF, a temporal compression, and an intensity for stimulation of the region of the brain; and applying focused ultrasound to the region of the brain with the selected PRF, the selected temporal compression, and the selected intensity.

[0020] The parameter sweep in the PRF parameter space may be conducted in a range from 1 Hz to 80 Hz. The parameter sweep in the temporal compression parameter space may be conducted in a range from 1% duty cycle (D.C.) to 40% D.C. The parameter sweep in the intensity parameter space may be conducted in a range from 0.1 W / cm2to 16 W / cm2. The detecting can be performed at single-cell resolution. The selecting of one or more of the PRF, the temporal compression, or the intensity can be based at least in part on an indication that the PRF, the temporal compression, or the intensity excites a particular cell type present in the region of the brain. The selecting of one or more of the PRF, the temporal compression, or the intensity can be based at least in part on an indication that the selected PRF, the selected temporal compression, or the selected intensity inhibits a particular cell type present in the region of the brain. The selecting of the PRF may occur before the parameter sweep in the temporal compression parameter space and the parameter sweep in the temporal compression parameter space is conducted at the PRF, or wherein the selecting of the PRF occurs before the parameter sweep in the intensity parameter space and the parameter sweep in the intensity parameter space is conducted at the PRF.

[0021] For purposes of summarizing the disclosure, certain aspects, advantages and novel features of the innovations have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, the innovations may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIGS. 1A and 1B schematically illustrate systems for combined ultrasonic stimulation and fiber photometry.

[0023] FIG.1C is a diagram illustrating cell-type specific labeling of cells exposed to ultrasound simulation an optical GCaMP excitation light.

[0024] FIG. 1D illustrates a computational model of acoustic pressure at the fiber optic tip of the optical fiber of FIG.1B.

[0025] FIG. 1E illustrates a summary of the ways focused ultrasonic stimulation can influence a subject.

[0026] FIG. 2 diagrams a process of ultrasound parameter space scanning across pulse repetition frequency (PRF), temporal compression, and intensity.

[0027] FIG. 3 is a flow chart showing a method of using a combined ultrasonic stimulation and fiber photometry device for determining excitatory or inhibitory ultrasound stimulation parameters.

[0028] FIG.4 illustrates a stimulation system that can stimulate a subject brain.

[0029] FIG.5 illustrates a method of stimulating a brain using a stimulation system, for example stimulation system of FIG. 4.

[0030] FIG. 6A depicts the positioning of the optical fiber within the subject mouse’s brain to detect stimulation of the CMT cells.

[0031] FIGS.6B–6G plot photometric response of the subject mouse’s CMT cells to ultrasound stimulation as a function of PRF, temporal compression, or intensity.

[0032] FIG. 7A depicts positioning of the optical fiber within the subject mouse’s brain to detect stimulation of the DMH, LC, and BNST cells.

[0033] FIGS. 7B–7D plot photometric response of the subject mouse’s DMH, LC, and BNST cells to ultrasound stimulation as a function of PRF, temporal compression, or intensity.

[0034] FIG.7E plots spline fits of the features examined in FIGS.7B–7D.

[0035] FIG. 8A diagrams automated video tracking methods for examining walking, anxiety, and head motion of subject mice.

[0036] FIGS.8B–8E plot changes of subject behavior in response to stimulation of CMT, BNST, or LC cells.

[0037] FIG. 9A illustrates positioning of the LH and DMH cells as well as the intensity of stimulation relative to the LH and DMH cells.

[0038] FIG.9B plots walking speed and %SAP as a function of time for DMH and LH stimulation, showing effects on walking after stimulation onset.

[0039] FIG. 9C diagrams the rotarod task, which involved the subject walking on a rotating rod.

[0040] FIGS.9D and 9E plot time to fail in the rotarod experiment for DMH, LH, and LC stimulation.

[0041] FIG. 10A diagrams a probe having a thermocouple.

[0042] FIGS. 10B and 10C plot changes in temperature over time at the focus of the probe.

[0043] FIG. 10D plot temperature change for the excitatory and inhibitory protocols.

[0044] FIG.10E diagrams a measurement scheme where rhodamine B dextran was injected into the test animal’s bloodstream and non-overlapping optical spectra was measured to simultaneously examine calcium of neurons with GCaMP6s.

[0045] FIG. 10F plots time series averages of neural activity and blood fluorescence relative to focused ultrasound (FUS) stimulus.

[0046] FIGS. 10G and 10H plot time series averages of neural activity (G) and blood volume at the CMT with and without COX inhibitor or saline vehicle administration prior to FUS stimulation with individual change across post stimulus period.

[0047] FIG. 11A illustrates a PhoCUS apparatus for simultaneous recording of brain GCaMP and blood volume.

[0048] FIG. 11B plots time series averages of neural activity for arousal regions during blood fluorescence monitoring of FUS.

[0049] FIG. 11C plots time series averages of blood fluorescence for all arousal regions during FUS stimulation with quantification during post-FUS period.

[0050] FIG. 11D illustrates a system for simultaneous functional ultrasound imaging and stimulation with an intensity overlay.

[0051] FIG. 11E shows a representative time series of changes in cerebral blood volume (ǻCBV) relative to a 5 s FUS stimulation.

[0052] FIGS.11F and 11G show example 2D brain segmentation for quantification time series averages of ǻCBV across different brain areas during FUS stimulation with quantification during post-FUS period. DETAILED DESCRIPTION

[0053] The following detailed description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals and / or terms can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and / or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings.

[0054] The use of ultrasound to non-invasively modulate behavior of the brain is a growing area of research given its relatively high spatial and temporal specificity. Studies have demonstrated that select intensities, frequencies, and modulation patterns of ultrasound can alter neuronal and brain-network activity. Neuromodulation using ultrasound therefore has great potential to non-invasively treat a wide array of neurological disorders, including epilepsy, essential tremor, depression, and sleep disorders.

[0055] Parameter optimization is believed to be significant for implementation of focused ultrasound in neuropsychiatric disorders in humans. Since focused ultrasound stimulation has so many variables and potential parameters for any given cell type, optimization methods offer a streamlined protocol to target different brain regions in freely behaving animals, potentially reducing the costs of optimization in clinical trials.

[0056] The select intensities, frequencies, and modulation patterns that can enhance and / or suppress neurological activity are an open area of study and have not yet been well-established. Furthermore, how functionally distinct cell-types respond to these ultrasound waveform features is not well known. This shortcoming is a barrier to ultrasound neuromodulation replacing and / or supplementing pharmacological psychiatric treatments.

[0057] Electrical recording from populations of neurons can lack the capacity to distinguish the genetically defined cell-types generating the recorded signal. In this case, the signaled neural response to a given treatment may not be emanating from a desired target. Optical readouts of neuronal activity have become a significant tool in neuroscience, because they can be genetically targeted to specific cell-types. However, optical access to sub- superficial regions of the brain can be limited due to the light-scattering effects of tissue. To circumvent this limitation, implanting optical fiber into the brain is an approach for optically measuring sub-superficial cell type activity. This method also benefits from its ability to transmit the signal over a distance using a light-weight implant and fiber optic cable, allowing the animals to behave freely during recording. However, this method can pose a significant issue for the delivery of ultrasonic waves as the fiber can block and / or diffract waves passing from tissue across the fiber as they penetrate the brain. Thus, accurately measuring sub- superficial cell-type response to ultrasound is currently infeasible.

[0058] Focused ultrasound waveforms can be tuned to specific brain regions and cell types to gain remote control over complex behaviors and physiology. However, the parameter space in focused ultrasound is multidimensional (carrier frequency, pulse repetition frequency, intensity, duration, etc.) and vast, and varies across neuronal cell types. Optimization tools are desired to narrow the range of stimulation parameters in a given cell type. The present disclosure provides for methods and systems for determining suitable stimulation parameters for different regions of the brain. The present disclosure also provides for systems and methods of stimulating a region of the brain using the suitable stimulation parameters. Parameters that affect ultrasound stimulation efficacy can include pulse repetition frequency (PRF), temporal compression, and intensity.

[0059] Aspects of this disclosure relate to combining deep-brain optical readouts with focused ultrasound technology to determine waveforms for inducing bidirectional neuromodulation across a collection of therapeutically significant brain cell types. Optimal and / or desirable ultrasound neuromodulation parameters can generalize across neuronal cell types. Distinct parameters for excitation and inhibition are identified herein. Target stimulation can induce sight specific behavioral changes. COX2-dependent vasoconstriction and brain cooling can occur with excitatory protocols disclosed herein.

[0060] Disclosed herein is usage of a device combining ultrasonic stimulation with fiber photometry for determining optimal and / or desirable ultrasound stimulation parameters of various portions of the brain. Such an approach allows for simultaneous recording of neuronal activity with cell-type specificity in response to ultrasonic neuromodulation. Also disclosed are systems, devices, and methods using selected ultrasound parameters when delivering ultrasonic neuromodulation to highly restricted areas of the brain. Overview of System

[0061] FIG. 1A shows a schematic drawing of a system 100 for combined ultrasonic stimulation and fiber photometry. The system 100 can include a computer (CPU) 102, a function generator 104, a power amplifier 106, a photodetector 108, a dichroic mirror 110, an optical fiber 112, a power cable 114, a cannula 116, a cranial interface 130, and a light source 132. The cranial interface 130 may further include a shaft collar 118, a set screw 120, an air backing layer 122, a piezoelectric element 124, a matching layer 126, and a coupling- gel bracket 128.

[0062] The cranial interface 130 can secure to a skull of a subject 134. In FIG.1A, the subject 134 is illustrated as being a mouse. The optical fiber 112 can be implanted in the brain of the subject 134. The photodetector 108, the dichroic mirror 110, the optical fiber 112, and the light source 132 can each be in optical communication. The light source 132 can provide light to the brain of the subject 134 via the optical fiber 112. The light source 132 can be a laser, such as a 473 nanometer laser. The light source 132 can be any other suitable light source. In some examples, there may one or more bandpass filters and / or lenses in communication with the photodetector 108, the dichroic mirror 110, the optical fiber 112, and the light source 132, for example, between the photodetector 108 and dichroic mirror 110 and / or between the light source 132 and the dichroic mirror 110. The dichroic mirror 110 can direct light from the light source 132 to the brain of the subject 143.

[0063] The shaft collar 118 together with the set screw 120 can secure the cannula 116 within the cranial interface 130. The air backing layer 122 can act to dampen vibrations from the piezoelectric element 124 from being transmitted away from the subject 134. The matching layer 126 can assist in transferring ultrasound energy from the piezoelectric element124 to the brain of the subject 134 smoothly such that signal loss is minimized due to mismatch in substrate mechanics. The coupling-gel bracket 128 provides an open volume for loading with gel (e.g., ultrasound transducer silicone grease) to aid in transmission of ultrasound energy between the piezoelectric element 124 and brain tissue.

[0064] An ultrasonic transducer can be integrated into the optical probe. For example, as shown in FIG.1A, the piezoelectric element 124 can be ring-shaped and included in the cranial interface 130. The piezoelectric element 124 can include electrical connections putting the piezoelectric element 124 in electrical communication with the power amplifier 106 via the power cable 114. The open center of the ring of the piezoelectric element 124 can allow light to pass from the brain of subject 134 along the optical fiber 112. When the piezoelectric element 124 is excited with a voltage, the piezoelectric element 124 can send ultrasonic energy into the cannula 116 and the optical fiber optical fiber 112. The piezoelectric element 124 can create an acoustic field in a volume at the tip of the optical fiber 112 implanted within the brain. The piezoelectric element 124 can be sufficiently thin such that the piezoelectric element 124 does not significantly compromise the photometry signal. The power amplifier 106, the function generator 104, and the CPU 102 can each affect the ultrasonic signal sent from the piezoelectric element 124. The CPU 102 can receive detected signal from the light source 132. The CPU 102 may be capable of fitting curves to data received from the light source 132.

[0065] Another example combined ultrasonic stimulation and fiber photometry device 10 is shown schematically in FIG.1B. An optical fiber 11 can be implanted in the brain of the subject, such as a mouse. Accordingly, the optical fiber 11 is an example of a brain implantable optical delivery element. In the combined ultrasonic stimulation and fiber photometry device 10, the optical fiber 11 is held by a cannula 12. The cannula 12 can be a steel cannula. A ferrule 13 is connected to the cannula 12 using a sleeve that slides over the ferrule 13 and the cannula 12. Accordingly, the ferrule 13 may be easily attached to and / or detached from the cannula 12. The ferrule 13 can be a steel ferrule. The fibers in the cannula 12 and ferrule 13 are aligned so that light can pass between them, connecting the fiber tip with the photometry system.

[0066] A fiber photometry system includes the optical fiber 11, the cannula 12, and the ferrule 13 connected to the cannula 12 by a sleeve, a dichroic mirror 14, a light source 15,a bandpass filter 16, a lens 17, and a photodetector 18. The light source 15 can provide light to the brain of the subject via the optical fiber 11. The light source 15 can be a laser, such as a 473 nanometer laser. The light source 15 can be any other suitable light source. The dichroic mirror 14 can direct light from the light source 15 toward the brain. The dichroic mirror can direct light from the brain to the photodetector 18 via the bandpass filter 16 and the lens 17. The photodetector 18 can detect a cell response to ultrasound applied to the brain. In certain instances, the photodetector 18 can detect a cell response with single cell resolution.

[0067] According to an embodiment, an ultrasonic transducer is integrated into the optical probe. For example, as shown in FIG. 1B, a ring-shaped piezoelectric element 19 is included between the cannula 12 and ferrule 13. The ferrule 13 and cannula 12 can be metallic and provide electrical connections to the electrodes on the top and bottom of the piezoelectric element 19. The open center of the ring of the piezoelectric element 19 can allow light to pass between the ferrule 13 and cannula 12. When the piezoelectric element 19 is excited with a voltage, the piezoelectric element 19 sends ultrasonic energy into the cannula 12 and the optical fiber 11. This can create an acoustic field in a volume at the tip of the optical fiber 11. The piezoelectric element 19 can be sufficiently thin such that the piezoelectric element 19 does not significantly compromise the photometry signal. Various features of each of the device 10 and the system 100 can be included in a device in accordance with the present disclosure.

[0068] FIG.1C is a diagram illustrating cell-type specific labeling of cells exposed to ultrasound simulation an optical GCaMP excitation light. The labeled cells 22 are exposed to ultrasound simulation and GCaMP excitation light near a tip of the optical fiber 11 of FIG. 1B. GCaMP is a genetically coded calcium indicator.

[0069] FIG. 1D illustrates a computational model of acoustic pressure at the fiber optic tip of the optical fiber 11 of FIG. 1B. The computation model of FIG. 1D demonstrates highly localized pressure.

[0070] FIG. 1E illustrates how stimuli having distinct parameters for excitation or inhibition can effectively cause neuromodulation in a subject. In the illustrated example, a relatively high-intensity and relatively short burst of stimulation can cause excitation, whereas a longer, lower-intensity stimulation can cause inhibition.

[0071] FIG. 2 diagrams a process of ultrasound parameter space scanning. Ultrasound parameter space scanning may be helpful for identifying optimal and / or desirableparameters for purposes of exciting or inhibiting activity of particular brain regions or brain cells. Parameter space scanning in accordance with the present disclosure includes scanning in the pulse repetition frequency (PRF) parameter space, in the temporal compression parameter space, and in the intensity parameter space. While a scan is being conducted in a particular parameter space, parameters in the other parameter spaces can be held constant. In some examples, a scan in the PRF is the first parameter space scan to be conducted. In some examples, a scan in the temporal compression space is the second parameter space scan to be conducted. Other ordering of parameter space scans may be suitable. In some examples, one or more additional parameter spaces may be scanned.

[0072] The parameter sweep in the PRF parameter space can be conducted in a range defined by any two of the following values (in Hz): 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In some examples, the parameter sweep in the PRF parameter space can be conducted from 1 Hz to 80 Hz. In some examples, the parameter sweep in the PRF parameter space can be conducted from 1 Hz to 40 Hz. The parameter sweep in the temporal compression parameter space can be conducted in a range defined by any two of the following values (in % duty cycle (D.C.)): 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50. In some examples, the parameter sweep in the temporal compression parameter space can be from 1% D.C. to 40% D.C. In some examples, the parameter sweep in the temporal compression parameter space from 1% D.C. to 20% D.C. The parameter sweep in the intensity parameter space can be conducted in a range defined by any two of the following values (in W / cm2): 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, or 32. In some examples, the parameter sweep in the intensity parameter space is conducted in a range from 0.1 W / cm2to 16 W / cm2. In some examples, the parameter sweep in the intensity parameter space is conducted in a range from 0.1 W / cm2to 8 W / cm2.Method of Determining Excitatory or Inhibitory Parameters

[0073] FIG. 3 is a flow chart of a method 300 of using a combined ultrasonic stimulation and fiber photometry device for determining excitatory or inhibitory ultrasound stimulation parameters.

[0074] At step 302, the ultrasound transducer and optical delivery element are portioned to simulate the target brain region.

[0075] At step 304, an ultrasound signal is transmitted to conduct one or more parameter sweeps. As discussed with reference to FIG.2, the parameter sweeps may be within at least the PRF parameter space, the temporal compression parameter space, and the intensity parameter space. A parameter sweep may be controlled by a hardware processor in communication with the ultrasound transducer. Such a hardware processor can be included in the CPU 102 of FIG.1A.

[0076] At step 306, and while step 304 is occurring, light is transmitted from a light source to the target brain region. Light can be generated by a light source and transmitted by an optical fiber of a device or system in accordance with any suitable principles and advantages disclosed herein.

[0077] At step 308, a response to ultrasonic stimulation is detected. The response can be detected by a photodetector that can detect changes in emitted light from the target brain region resulting from the ultrasonic stimulation. The photodetector can be the photodetector 108 of FIG.1A, for example. In some examples, the changes may be due to calcium responses of brain cells. Step 308 may be performed by a photodetector (e.g., a CMOS) in accordance with the present disclosure.

[0078] At step 310, parameter values are selected. The selected parameter values can be optimal parameter values and / or desirable parameter values. The selected parameter values may be based in part on a target brain region or target cell type. In some examples, parameter values in each of the parameter spaces may be selected to maximize or to minimize a light signal detected in step 308. In some examples, selecting an optimal parameter value may include identifying a local minimum, a local maximum, a global minimum, or a global maximum in light response resulting parameter space scan. In some examples, selecting optimal parameter values may depend in part on properties of brain cell signaling. In a further example, it may be desirable to select a PRF that is close in frequency to the natural frequencyof neuron activity. Step 310 may be carried out by a hardware processor in communication with the photodetector. For example, step 310 be carried out by the CPU 102 and the photodetector 108 of FIG. 1A.

[0079] At step 312, selected parameter values can be displayed. The hardware processor can cause a display to display the selected parameter values to a user.

[0080] A coordinate descent method for multi-parametric optimization of neural activity change across four distinct cell populations can be applied. Arousal centers can be selected with the goal of producing clearly observable changes in behavior. Optimized and / or selected protocols can elicit rapid and evident changes in behavior that can be speci¿c to each target and can be largely absent when applying non-optimized protocols. The physiological impacts of these protocols can lead to changes in focal brain temperature and blood volume, indicating powerful neuromodulation and protracted vascular effects. Overview of Stimulation System

[0081] FIG. 4 is a schematic block diagram of a stimulation system 400 that can stimulate a subject brain in accordance with the present disclosure. The system 400 can include a CPU 402, a function generator 404, a power amplifier 406, and an ultrasonic transducer 408.

[0082] The CPU 402 can store parameter data, such as parameter sweep curves, for each of a PRF parameter space, a temporal compression parameter space, and an intensity parameter space. The parameter data can be associated with a particular area of a brain. The CPU 402 can set the operating parameters of the ultrasound transducer 408 based at least in part on the stored parameter data (e.g., parameter sweep curves). For example, the CPU 402 may be capable of setting the operating parameters of the ultrasonic transducer 408 to inhibit or to excite a brain region and / or a cell type. The CPU 402 can select values of PRF, temporal compression, and intensity to maximize cell activity or minimize cell activity. The CPU 402 can select any suitable values of PRF, temporal compression, and intensity for a desired cell response. Such parameter values can be produce a desired response that is less than the maximum cell activity or more than the minimum cell activity. The CPU 402 can select parameters based on a particular area of a brain being simulated so that parameter data associated with the particular area of the brain is used in parameter selection.

[0083] The function generator 404 and power amplifier 406 can translate signals from the CPU 402 to cause the ultrasonic transducer 408 to emit ultrasonic waves. In some examples, the CPU 402 may be integrated with the function generator 404, or the CPU 402 may be integrated with the function generator 404 and the power amplifier 406.

[0084] In some examples, the ultrasonic transducer 408 may be non-invasive. In some examples, the ultrasonic transducer 408 may be minimally invasive. The ultrasonic transducer 408 can, when in use, deliver ultrasonic waves to tissue of a user’s brain. Method of Stimulation

[0085] FIG. 5 illustrates a method 500 of stimulating a brain using a stimulation system, for example stimulation system 400.

[0086] At step 502, the brain region and / or the cell type is selected. As discussed herein, different regions of the brain or different cell types may be excited or inhibited by different ultrasonic transducer operating parameters.

[0087] At step 504, the ultrasonic transducer is positioned. The ultrasonic transducer should be positioned so that it can stimulate the target brain region and / or target cell type. As discussed herein, positioning of the ultrasonic transducer can affect which region of the brain is stimulated.

[0088] At step 506, ultrasound parameters are set. A hardware processor or CPU can be used to set ultrasound operating parameters. Such setting may be based at least in part on parameter sweeps in the PRF parameter space, the temporal compression parameter space, and the intensity parameter space.

[0089] At step 508, ultrasonic energy is applied to the subject’s brain using an ultrasound transducer. The ultrasound transducer can be controlled by the hardware processor or CPU setting the ultrasound operating parameters. EXAMPLES Example 1. Optimizing excitation and inhibition of deep brain arousal centers

[0090] Three ultrasound parameters were selected for examination. The first of these parameters was pulse repetition frequency (PRF), which, without being bound to a particular theory, is believed to play a role in neuromodulation across modalities such as deepbrain, optogenetic, and transcranial magnetic stimulation. The second of these parameters was temporal compression, which inversely varies pulse duration and pulse train duty cycle. When varying temporal compression, total power delivery was kept constant. For instance, a 2-fold compression would be achieved by reducing duration by half and doubling duty cycle. Varying this temporal compression may be used to limit the tissue heating associated with ultrasound absorption. The third of these parameters was spatial peak pulse average intensity (ISPPA). Given the vast parametric space available, a feed-forward coordinate descent strategy was used, where optima for each parameter are successively derived independently, while all other features remain constant. Each optimal coordinate was then passed on as a constant for examination of the subsequent parameter, for example as discussed with reference to FIG. 2 above.

[0091] Ca2+calmodulin-dependent protein kinase II positive (CAMKII+) excitatory neurons of the central medial thalamus (CMT) were examined. GCaMP6s was virally expressed under the CAMKII promoter in the CMT, and an optical fiber implanted immediately dorsal to it, as shown in FIG. 1A. The positioning of the optical fiber within the subject mouse’s brain is depicted in FIG.6A. To deliver focused ultrasound to the target area, a mountable ring transducer was used at an operating frequency of 550 kHz. The field full- width half-maximum was ~2.3 mm lateral (wide) and 7.2 mm axial (long) with the focal peak at ~6 mm from the transducer face, not accounting for standing waves which may affect the field intensity heterogeneously. Ultrasound was pulsed with 5 different PRFs ranging from 2.5 Hz up to 40 Hz while maintaining a fixed pulse train duty cycle of 20%, an intensity of 3.7 W / cm2, and pulse train of 5 seconds. As shown in FIG.6B, lower PRFs with longer individual pulse durations appear to increase neuronal activity detectable in the GCaMP6s signal during the stimulation period (Q1; 0-5s post stimulation onset), with the largest increase at 2.5 Hz. Post-stimulation inhibition was quantified using a time window inclusive of any observed decrease in neural activity below baseline across the animal-averaged response (10-85 seconds post stimulation onset). During this period, as shown in FIG. 6C, there was a non-monotonic response curve of neural inhibition to PRF where 20 Hz pulsing significantly suppressed activity.

[0092] With a PRF of 2.5 Hz selected for excitation and 20 Hz for inhibition, PRF parameters were passed onto the temporal compression step. The duration of pulsing wasincrementally increased while duty cycle decreased, such that total power delivery was held constant. For stimulus locked effects, the response was quantified over the longest duration (0- 40s post stimulation onset) to be inclusive of all protocol stimulus periods. Compression appears to enhance excitation of the 2.5 Hz excitatory parameter (FIG.6D, maximal excitation at 5-seconds, 20% duty cycle), whereas decreasing compression with the 20 Hz pulsing appears to cause the greatest inhibition (FIG. 6E, 40-seconds 2.5% duty cycle). Power was incrementally increased, from a spatial peak intensity of 0.3 to 7.4 W / cm2. Excitation during the stimulus was achieved even at lower intensities, with peak excitation at 5.4 W / cm2(FIG. 6F). As shown in FIG. 6G, inhibitory protocol intensity showed post stimulus suppression at 3.7 W / cm2. Example 2. Determining optimal parameters across other brain areas and cell-types

[0093] A second cell type was chosen for comparison with the CAMKII+ CMT neuron results discussed above. Dorsomedial hypothalamic (DMH) GABAergic neurons, Locus Coeruleus (LC) noradrenergic neurons, and GABAergic neurons of the Bed Nucleus Stria Terminalis (BNST) were selected. Positioning of an optical probe to detect stimulation of DMH, LC, and BNST cells is diagrammed in FIG. 7A. A DLX-promoter driven GCaMP6s was used for the examination of DMH or BNST GABA positive neurons and a Tyrosine Hydroxylase promoter mouse strain (TH-flpO+) with a flp-dependent GCaMPP6s viral element was used to examine TH+ LC neurons. DLX+ DMH and TH+ LC neurons showed stimulus-locked response to all PRFs, with the largest increases at lower PRFs, as shown in FIG. 7B. BNST neurons did not show activation at any tested PRF, but did show a decrease during the post-stimulus period at 20 Hz stimulation, as shown in the BNST plot of FIG.7B.

[0094] As shown in FIG.7C (LC plot), LC neurons showed excitation at 5-seconds 20% D.C. The DMH responded maximally at 10-second, 10% D.C. compression, as shown in FIG. 7C . BNST neurons did not show significant suppression at any compression of the 20 Hz protocol. As shown in FIG.7D, both the LC and DMH neurons showed increased response during stimulation with increasing intensity. FIG.7E shows trends for feature response profiles across the various cell types examined, demonstrating different optimal parameters and differences in response magnitude. Despite previous findings that inhibitory interneurons may inhibit their excitatory outputs, CAMKII+ neurons of the paraventricular nucleus (PVN),which are in close proximity to the DMH (~0.4 mm), and receive inhibitory inputs from the GABAergic DLX+ neurons, were still excited by the same DMH targeted stimulus. The focused ultrasound (FUS) induced neural response was larger than that generated by a very loud 16 kHz, 96dB tone with the same envelope played in the animal’s environment. These findings indicate that the optimized ultrasound protocol not only overrides local inhibitory inputs, but also produces larger excitation than salient external stimuli.

[0095] To examine the extent to which neural response was due to non-specific effects arising from peripheral auditory or tactile stimulation, z-axis adjustability of the photometry coupled ultrasound (PhoCUS) probe was used to move the focus 3 mm dorsal to each target. This adjustment placed the focal peak closer to cortical areas and skull bone, which may result in greater shear wave propagation to the cochlea, and louder audible sound. With the off-target focus, the cell types showed reduced response without significant modulation at any intensity, suggesting that audition may not play a dominant role in the observed response. Example 3. Focused ultrasound (FUS) and target-specific behavioral effects

[0096] The thalamus, hypothalamus, and locus coeruleus are all believed to be linked to varying levels of consciousness, anxiety, and locomotion. It may be possible to manifest visible changes in behavior based on changes to the thalamus, hypothalamus, and locus. To examine whether differences in neuromodulation corresponded with overt behavioral changes, neural measurements were coupled with visual ethological monitoring. As diagrammed in FIG. 8A, automated video tracking was used to quantify changes in head motion, walking, and body shape of subject mice while stimulating the various brain targets at optimal excitation or inhibition. With reference to FIG. 8B, targeting the CMT with the CAMKII+ optimized excitatory waveform appears to cause an increase in head motion during the stimulus. There appeared to be a significant decrease in head motion when applying the inhibitory protocol during the dark phase. Since changes in head motion were not observed when CMT-optimized inhibitory parameters were applied to the BNST or LC, these results may suggest that optimizing parameters for activation and inhibition of local cell types can achieve selective and bidirectional control of behavior.

[0097] Now with reference to FIG. 8C, when targeting the DMH, stimulation appeared to produce an increase in walking which extended beyond the stimulation period.With reference to FIG. 8D, Animals also exhibited a rapid and transient increase in stretch attend posture (SAP), a behavior which can manifest during increased states of anxiety. With reference to FIG. 8E, when the animals were not walking, head motion appeared to significantly increase, which may indicate some level of arousal and dynamic investigation of their environment. To examine whether the optical optimizations had any bearing on behavioral outcomes, the DMH was stimulated with the same intensity and duty cycle, but with a suboptimal PRF of 20 Hz that results in less activation of local neurons (see, for example, FIG. 7B). With reference to FIG. 8C, this waveform difference appears to have eliminated significant walking induction. With reference to FIGS. 8D and 8E, suboptimal stimulation still increased SAP, but both SAP and head speed were reduced during the sub- optimal protocol, in comparison to the optimized waveform. With reference to FIG. 8C, the DMH optimized protocol targeted to either the BNST or LC did not result in any significant increases in walking, SAP, or head motion, which may indicate that these behavioral effects are both target- and waveform-specific.

[0098] Repeated FUS stimulation of the DMH did not lead to a significant reduction in successive neuronal activation or walking response. CMT neural activity and behavioral response appeared to significantly change with latter trials being significantly lower than the first trial. To assess whether the optical fiber was necessary for FUS induced behavioral changes, cannulas were mounted absent optical fiber implant, and found behavioral response was maintained. The behavior was eliminated by moving the focus 3 mm posterior to the target, which may further demonstrate the specificity of brain area targeted for behavioral intervention. To compare FUS stimulation to another neuromodulatory modality, optogenetic stimulation of the DMH was performed using pan-neuronal expression of ChRmine below the optical fiber. 10 Hz pulsing elicited a similar increase in walking and head speed, which may indicate that stimulation of the hypothalamus can elicit locomotion. In this experiment, SAP was not significantly increased, suggesting the broader ultrasound field might engage SAP through a neighboring hypothalamic brain area.

[0099] Hypocretin neurons of the lateral hypothalamus (LH), a region positioned ~0.7 mm lateral to the DMH, may be involved in arousal and the behavioral manifestation of stress and anxiety. With reference to FIG. 9A, the focus was positioned onto the LH while recording hypocretin neuron activity and behavior in Hcrt-cre animals. With reference to FIG.9B, stimulation of the LH increased walking only during FUS stimulation, in comparison to the DMH stimulation which increased walking for up to 30 seconds after the stimulus onset. With reference to FIG.9B, LH stimulation resulted in extended SAP, lasting up to 40 seconds post stimulation, while DMH stimulation only increased SAP during the stimulus, a significant difference between stimulation of the two brain areas. FIG. 9C diagrams the rotarod task, which involved the subject walking on a rotating rod. Time was measured between FUS onset and task failure (e.g., falling of the rotating rod). With reference to FIGS. 9D and 9E, there appears to be a correlation between each animal’s change in rotarod failure time and their free field walking but found no correlation with their change in SAP. This interruption of walking behavior was not observed during LC stimulation, which may indicate the specificity of this response to the hypothalamic locomotor region, for example, as shown in FIG.9D. Example 4. FUS-induced local brain cooling and cyclooxygenase dependent vasoconstriction

[0100] The excitatory protocols can deliver energy more rapidly to the brain than inhibitory protocols. Accordingly, whether FUS induced temperature increases may cause differences in neuromodulation, as observed in various neural structures, was examined. The optical fiber of a device or system in accordance with the present disclosure was replaced with a thermocouple and used to monitor local brain temperature at the ultrasound focus and immediately beneath the skull when targeting the CMT as diagrammed in FIG.10A. As shown in FIGS. 10B and 10C, and in contrast to the generally accepted notion that FUS increases tissue temperature, the modified device measured a decrease in temperature at the focus by nearly 1 °C.

[0101] With reference to FIG. 10D, the excitatory and inhibitory protocols increased temperature immediately above the cortex by up to 1.49 °C and 0.72 °C, respectively, perhaps because the skull is absorbent of ultrasound waves and the probe itself can produce heat. Blood flow can act as a convective pump to distribute heat around the brain.

[0102] With reference to FIG.10E and to examine whether blood volume changed at the focus, rhodamine B dextran 1004 was injected into the animal’s bloodstream and used the non-overlapping optical spectra to simultaneously measure calcium of neurons 1002 with GCaMP6s. Both the rhodamine B dextran 1004 and calcium of the neurons 1002 were measured with an optical probe 1006 in accordance with the present disclosure.

[0103] As shown in FIGS. 10F and 10G, a rapid increase in CAMKII+ CMT neuronal activity appeared to be correlated with a rapid rise in blood volume; consistent with neurovascular coupling observed with other imaging modalities. With reference to FIG. 10G, following the initial spike in blood volume, there appeared to be a sustained decrease in volume over the 3-minute interstimulus period. Cyclooxygenase 1 and 2 (COX1 / 2) may couple brain activity to vasodynamics bidirectionally.

[0104] Although normal increases in neural activity promote vasodilation, substantial increases in neural activity can drive delayed and prolonged vasoconstriction. To examine this possible link between vasoconstriction and neural activity, blood volume and neural activity were measured in the CMT following ibuprofen (30 mg / kg, a COX1 / 2 inhibitor) or saline injection. FIGS. 10G and 10H show that neural activity underwent no apparent change, and that the decrease in blood volume was eliminated, suggesting that strong FUS activation can drive long-lasting neurovascular responses through canonical COX1 / 2 signaling.

[0105] To examine whether this phenomenon was related to differences in observed neural activity which varied across brain areas, blood volume following optimized stimulation (2.5 Hz, 10-s, 10% D.C.) of the DMH, LC, and BNST were measured. As shown in FIGS. 11A, 11B, and 11C, all three regions showed significant vasoconstriction following the stimuli despite the lesser activation observed in the LC and BNST. Like the CMT, all regions also appeared to maintain a correlation of vasodilation with neural activity during the FUS stimuli. Increased neural activity did not appear cause larger post-stimuli vasoconstriction for any region. Larger neural activity appeared to be associated with modest vasodilation for the CMT. This disassociation suggested that vasoconstriction may be driven by FUS effects beyond local neural activity. To examine the spatial breadth of these effects, ultrafast power doppler imaging were combined with focused ultrasound stimulation to measure cerebral blood volume changes across the focal plane in anesthetized mice. The findings are plotted in FIGS. 11D and 11E. With reference to FIG.11D, the optimized stimulus pulsing (2.5 Hz, 20% D.C., 5 sec) was targeted to the CMT using a similar fundamental frequency (500 kHz), intensity (18.9 W / cm2) and focal area. With reference to FIGS. 11E, 11F, and 11G, significant vasoconstriction appeared to occur broadly across the thalamus, hypothalamus, and cortex. The hippocampus appeared to be resilient against vasoconstriction, which may suggest thatvasodynamic response propagates beyond the ultrasound focus in a brain region dependent manner.

[0106] Despite the changes in neural activity, behavior, and vascular responses, changes in blood corticosterone levels or peripheral immune responses were not observed following repeated DMH stimulation (10 stimulations, 3-min interval). This may indicate that the observed behavioral and neurovascular effects were due to neuromodulation rather than non-specific consequences of FUS stimulation and supports the safety of repeated FUS brain stimulation to deep brain targets, including the hypothalamus. Conclusion

[0107] Focused ultrasound can non-invasively modulate neural activity. Fiber photometry coupled focused ultrasound in freely behaving animals can be used to optimize waveform architecture across different neural populations. For all cell types, relatively low frequency, compressed, relatively high intensity pulsing can maximize neural response; inversion of these features can cause cell type selective, sustained neural inhibition with particular potency in the betagamma range. Examining cortical representation of deep brain stimulation showed that targeting thalamic circuitry resulted in sustained increases somatosensory and visual activity indicating increased engagement. To examine whether the waveform tuning enhanced behavioral outcomes we examined freely moving behavior and found that GABAergic dorsomedial hypothalamus excitation could elicit stimulus locked walking and anxiety behavior capable of overriding natural motivated behavior, whereas non- optimized protocols of equivalent energy or alternate-target exposure resulted in substantially less or no change in behavior. Bidirectional manipulation of the centromedian nucleus activity could increase or decrease head movement through similar total energy delivery indicating altered attention. In examining whether thermal effects could explain neurobehavioral differences, we found that activating protocols induce local cooling in the brain through cyclooxygenase dependent vasoconstriction. Together, these findings demonstrate that, with proper tuning, pure focused ultrasound can exhibit powerful effects on complex behavior and physiological state.

[0108] A relatively wide array of ultrasound pulsing parameters and optimal parameters for both excitation and inhibition across various cell types were examined. Evensubtle changes in these parameters resulted in relatively large differences in neuronal activity and ultrasound-induced behavioral outcomes. In examining the impact of PRF on neuromodulation, clear and bidirectional differences were identified within a relatively narrow frequency band. PRF can be inversely related to excitation, with lower frequencies having stronger excitation. For FUS intensity, stimulus-locked neural activity can increase with intensity across all cell types.

[0109] This disclosure provides a framework for examining and selecting and / or optimizing FUS neuromodulation across brain regions and cell types. Focused ultrasound can non-invasively modulate neural activity. Focused ultrasound coupled with ¿ber photometry can be used to identify optimal neuromodulation parameters for a variety of (e.g., four) different arousal centers of the brain in an effort to yield overt changes in behavior. Applying coordinate descent, optimal parameters for excitation or inhibition can be highly distinct. The effects of such parameters can generally be conserved across brain regions and cell types. Optimized parameters can induce clear, target-speci¿c behavioral effects, whereas non- optimized protocols of equivalent energy can instead result in substantially less or no change in behavior. The outcomes of ultrasound stimulated with optimized parameters were independent of auditory confounds and, contrary to expectation, accompanied by a cyclooxygenase-dependent and prolonged reduction in local blood Àow and temperature with brain-region-speci¿c scaling. Carefully tuned and targeted ultrasound can exhibit powerful effects on complex behavior and physiology in accordance with aspects of this disclosure.

[0110] Parametric optima were discovered in accordance with aspects of this disclosure and are largely conserved across various cell types in the brain. Relatively low frequency, compressed, relatively high intensity protocols can drive neuronal excitation. 20 Hz pulsing with a relatively long duration and relatively low duty cycle can be inhibitory for select cell types.

[0111] Optimized protocols can have powerful effects on network activity and behavior. Optimized stimulation of the dorsomedial hypothalamus can cause differential cortical response patterns and induce sustained walking which can override naturalistic locomotion. Slight biasing of focal position to the lateral hypothalamus can increase anxiety and decrease walking behavior and allow naturalistic walking. Bidirectional protocolsidentified for the centromedian thalamic nucleus can be used to either increase or decrease arousal monitored through head motion.

[0112] Certain excitatory protocols can cause local brain cooling. Thermocouple probing of focal brain temperature shows an average cooling of -1 °C in certain instances. FUS can induce vasoconstriction through cyclooxygenase dependent signaling, likely increasing CSF convective flow and heat displacement.

[0113] In the embodiments of this disclosure, the apparatus, systems, and methods for ultrasound neuromodulation are described in connection with particular embodiments. It will be understood, however, that the principles and advantages of the embodiments can be used for any other systems, apparatus, or methods with a need for ultrasound neuromodulation. The elements and acts of the various embodiments of this disclosure can be combined to provide further embodiments. The acts of the methods discussed herein can be performed in any order as appropriate. Moreover, the acts of the methods discussed herein can be performed serially or in parallel, as appropriate. Moreover, any suitable principles and advantages of this disclosure in systems and in methods that include an antenna array.

[0114] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and / or states. Thus, such conditional language is not generally intended to imply that features, elements and / or states are in any way required for one or more embodiments or whether these features, elements and / or states are included or are to be performed in any particular embodiment.

[0115] Unless the context clearly requires otherwise, throughout the disclosure and the claims, the words “comprise,” “comprising,” “include,” “including,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The words “coupled” or connected”, as generally used in this disclosure, refer to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.

[0116] Where the context permits, words in this disclosure using the singular or plural number may also include the plural or singular number, respectively. The words “or” in reference to a list of two or more items, is intended to cover all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. All numerical values provided herein are intended to include similar values within a measurement error.

[0117] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel ultrasound neuromodulation systems and methods of this disclosure may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. Such changes and modifications are to be understood as being included within the scope of the disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and / or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described herein can be combined to provide further embodiments. The various features and processes described above may be implemented independently of one another or may be combined in various ways. All possible combinations and sub-combinations of features of this disclosure are intended to fall within the scope of this disclosure.

Claims

WHAT IS CLAIMED IS:

1. A method of stimulating a region of a brain of a subject, the method comprising: accessing parameter data stored in a hardware processor, the parameter data associated with a plurality of parameter sweeps, the parameter data comprising data associated with ultrasonic pulse repetition frequency (PRF), ultrasonic temporal compression, and ultrasonic intensity for a target region of the brain; setting parameters of an ultrasound transducer for the target region of the brain, based at least in part on the parameter data; and applying ultrasound energy to the target region of a brain using an ultrasonic transducer to excite cells in the target region of the brain, the ultrasound energy exhibiting the set parameters, wherein a temperature of the target region of the brain is reduced from the applying.

2. The method of claim 1, wherein the applied PRF is a frequency below 10 hertz (Hz).

3. The method of claim 1, wherein the applied compression is a compression ranging from 5% to 15% duty cycle (D.C.).

4. The method of claim 1, wherein the setting is based at least in part on a target cell type.

5. The method of claim 1, comprising generating the parameter data.

6. The method of claim 5, where the generating the parameter data comprises conducting the parameter sweeps in the PRF parameter space, in the compression parameter space, and in the intensity parameter space.

7. The method of claim 5, where the generating the parameter data comprises measuring a plurality of GCaMP responses to ultrasonic stimulation.

8. The method of claim 7, wherein the measuring the plurality of GCaMP responses is conducted using a fiber photometer.

9. A system for stimulating a region of a brain of a subject, the system comprising: an ultrasound transducer configured to transmit ultrasonic energy to the region of the brain of the subject; and a hardware processor in communication with the ultrasound transducer, the hardware processor configured to: set operating parameters of the ultrasound transducer associated with a target region of the brain, wherein the parameters comprise pulse repetition frequency (PRF), temporal compression, and intensity, and cause the ultrasound transducer to transmit the ultrasonic energy to the target region of the brain based on the set operating parameters.

10. The system of claim 9, further comprising memory storing parameter data for each of the operating parameters for the target region of the brain, wherein the hardware processor is configured to access the parameter data and set the operating parameters based on the operating parameter data.

11. The system of claim 10, wherein the parameter data comprises parameter sweep curves for each of a PRF parameter space, a temporal compression parameter space, and an intensity parameter space.

12. The system of claim 9, wherein the hardware processor is configured to cause the ultrasound transducer to operate at a PRF in a range from 10 hertz (Hz) to 30 Hz.

13. The system of claim 9, wherein the hardware processor is configured to set the operating parameters of the ultrasound transducer to excite a target cell type of the target region of the brain.

14. The system of claim 9, wherein the hardware processor is configured to set the operating parameters of the ultrasound transducer to inhibit activity of a target cell type of the target region of the brain.

15. The system of claim 9, further comprising an optical fiber configured to apply the ultrasonic energy transmitted by the ultrasound transducer to the target region of the brain..

16. A method of stimulating a region of a brain of a subject, the method comprising: setting parameters of an ultrasound transducer for a target region of the brain, wherein the parameters comprise pulse repetition frequency (PRF), temporal compression, and intensity; and applying ultrasound energy to the target region of a brain using an ultrasonic transducer to excite cells in the target region of the brain, the ultrasound energy exhibiting the set parameters.

17. The method of claim 16, wherein the applied PRF is in a frequency range from 10 HZ to 30 Hz.

18. The method of claim 16, wherein the applied compression is a compression ranging from 5% to 15% duty cycle (D.C.).

19. The method of claim 16, wherein the setting is based at least in part on a target cell type.

20. The method of claim 16, wherein the setting is based at least in part on accessing data associated with a plurality of parameter sweeps of a PRF parameter space, a temporal parameter space, and an intensity parameter space for the target region of the brain in a control subject.

21. A method of determining ultrasonic stimulation parameters for a region of a brain using a system configured for combined ultrasound stimulation and photometry, the method comprising: stimulating, using an ultrasonic transducer, the region of the brain while a tip of an optical delivery element is positioned at the region of the brain, wherein the stimulating comprises conducting a parameter sweep in a pulse repetition frequency(PRF) parameter space, a temporal compression parameter space, and an intensity parameter space; transmitting, while ultrasound stimulation is being applied to the region of the brain, light from a light source to the region of the brain via the optical delivery element; detecting, with a detector, a plurality of responses of the brain to the ultrasonic stimulation; and storing, in non-transitory memory, parameter data associated with the plurality of responses.

22. The method of claim 21, further comprising: selecting, based at least in part on the parameter data, a PRF, a temporal compression, and an optimal intensity for stimulation of the region of the brain; and applying focused ultrasound to the region of the brain with the selected PRF, the selected temporal compression, and the selected intensity.

23. The method of claim 21, wherein the parameter sweep in the PRF parameter space is conducted in a range from 1 Hz to 80 Hz.

24. The method of claim 21, wherein the parameter sweep in the temporal compression parameter space is conducted in a range from 1% duty cycle to 40% duty cycle.

25. The method of claim 21, wherein the parameter sweep in the intensity parameter space is conducted in a range from 0.1 W / cm2to 16 W / cm2.

26. The method of claim 21, wherein the detecting is performed at single-cell resolution.

27. The method of Claim 21, wherein the selecting of one or more of the PRF, the temporal compression, or the intensity is based at least in part on an indication that the PRF, the temporal compression, or the intensity excites a particular cell type present in the region of the brain.

28. The method of Claim 21, wherein the selecting of one or more of the PRF, the temporal compression, or the intensity is based at least in part on an indication that the PRF, the temporal compression, or the intensity inhibits a particular cell type present in the region of the brain.

Images