A collective array magnetically compatible infrared neural stimulation system

Abstract

The present invention discloses a collective array type magnetically compatible infrared neural stimulation system, which belongs to the field of medical devices, including a signal generator, the output end of the signal generator is connected to the input end of a trigger, the output end of the trigger is connected to the input end of a microcontroller, the output end of the microcontroller is connected to the input end of an optical path switcher and the input end of a pulse modulator, the output end of the pulse modulator is connected to a laser, the laser emits a laser light source to the optical path switcher, and the optical path switcher emits the laser light source to a multi-channel magnetically compatible optical fiber array; the diameters of the stimulation ports with different spatial distributions in the multi-channel magnetically compatible optical fiber array are all no more than 1 cm, and are integrated with a number of optical fiber channels with a diameter of 220 microns. The present invention adopts the above-mentioned collective array type magnetically compatible infrared neural stimulation system, and can meet the distribution of functional columns in different brain regions of different experimental animals at the same time, so as to achieve efficient exploration of functional connections at the scale of functional columns of the whole brain and flexibly modulate specific functions.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a collective array type magnetically compatible infrared nerve stimulation system. Background Art

[0002] In order to effectively use near-infrared lasers to stimulate and regulate brain function, the existing technology is mainly single-fiber stimulation, which accurately stimulates focal functional sites (submillimeter scale) by implanting a single optical fiber into the cortex, thereby studying the functional connection network of the site. Although single-fiber stimulation can reach deep brain regions, this technology has many limitations for surface brain regions of the cortex, mainly in the following aspects: (1) the replacement of stimulation sites is not flexible enough, requiring re-drilling and plugging and unplugging of optical fibers; (2) dynamic stimulation cannot be generated, and complex stimulation paradigms cannot be given; (3) if dynamic stimulation is required, multiple optical fibers need to be implanted at the same time, which is extremely challenging for surgical positioning and MRI coil placement. Summary of the invention

[0003] The purpose of the present invention is to provide a collective array type magnetically compatible infrared neural stimulation system to solve the problems mentioned in the above background technology.

[0004] To achieve the above-mentioned object, the present invention provides a collective array type magnetically compatible infrared neural stimulation system: comprising a signal generator, the output end of the signal generator is connected to the input end of a trigger, the output end of the trigger is connected to the input end of a microcontroller, the output end of the microcontroller is connected to the input end of an optical path switcher and the input end of a pulse modulator, the output end of the pulse modulator is connected to a laser, the laser emits a laser light source to the optical path switcher, and the optical path switcher emits the laser light source to a multi-channel magnetically compatible optical fiber array;

[0005] The diameters of stimulation ports with different spatial distributions in the multi-channel magnetically compatible optical fiber array are all no larger than 1 cm, and are integrated with a number of optical fiber channels with a diameter of 220 μm.

[0006] Preferably, the parameter adjustment range of the laser light source emitted to the multi-channel magnetically compatible optical fiber array is: the laser wavelength is 1875nm, the laser radiation energy is 0.1-1.0J / cm 2 The width of each stimulation pulse is 0.25 milliseconds, the frequency is 100-400 Hz, and the duration of the pulse sequence is not less than 8 milliseconds.

[0007] Preferably, the optical fiber material of the multi-channel magnetically compatible optical fiber array is silicon dioxide, and the shell material used to fix and encapsulate the optical fiber is lead-free glass.

[0008] Preferably, the channel switching speed in the multi-channel magnetically compatible optical fiber array is no more than 0.5 ms, and the error between the stimulation duration of each channel and the preset duration is no more than 3‰.

[0009] Preferably, a multi-level fiber optic switch connection is used to control channel switching.

[0010] Preferably, the photoelectric switch is a photoelectric switch based on a piezoelectric polarizer.

[0011] Therefore, the present invention adopts the above-mentioned collective array type magnetic compatible infrared neural stimulation system, which has the following beneficial effects:

[0012] (1) It solves the difficulty of long-distance projection in the near-infrared band, allowing the laser output to reach the cortex directly;

[0013] (2) Efficient and convenient multi-site laser stimulation without the need to implant multiple optical fibers or use multiple lasers simultaneously;

[0014] (3) The output channels can be freely switched through algorithm editing to flexibly deliver dynamic lasers of different modes to the cortex;

[0015] (4) A neural system imaging and recording platform that is compatible with multiple modalities such as magnetic resonance imaging, optical imaging, and electrical signal recording.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the overall system of an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a 100-channel magnetically compatible optical fiber array according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of a 101-channel magnetically compatible optical fiber array according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of a 72-channel magnetically compatible optical fiber array according to an embodiment of the present invention;

[0021] Figure 5 The overall software architecture diagram of the embodiment of the present invention;

[0022] Reference numerals

[0023] 1. Signal generator; 2. Trigger; 3. Microcontroller; 4. Optical path switcher; 5. Pulse modulator; 6. Laser; 7. Multi-channel magnetically compatible optical fiber array. DETAILED DESCRIPTION

[0024] Example

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Reference Figure 1 The present invention discloses a collective array type magnetically compatible infrared neural stimulation system, comprising a signal generator 1, the output end of the signal generator 1 is connected to the input end of a trigger 2, the output end of the trigger 2 is connected to the input end of a programmable microcontroller 3, the output end of the microcontroller 3 is connected to the input end of an optical path switcher 4 based on a piezoelectric polarizer and the input end of a pulse modulator 5, the output end of the pulse modulator 5 is connected to a laser 6, the laser 6 emits a laser light source to the optical path switcher 4 based on a piezoelectric polarizer, and the optical path switcher 4 based on a piezoelectric polarizer emits the laser light source to a self-designed multi-channel magnetically compatible optical fiber array 7.

[0027] Stimulation ports with different spatial distributions can be customized according to different needs, and are integrated with several optical fiber channels with a diameter of 220 microns. Figure 2 This is a schematic diagram of a 100-channel magnetically compatible fiber array, which is densely arranged (channel center distance 220um) and has a small coverage area (2mm*2mm), which is suitable for studying functional network connections within brain regions; Figure 3 This is a schematic diagram of a 101-channel magnetically compatible fiber array, which has a large arrangement interval (channel center distance 500um) and a large coverage area (5mm*5mm), which is suitable for studying functional network connections across brain regions; Figure 4 This is a schematic diagram of a 72-channel magnetically compatible fiber optic array, which has two columns of channels arranged linearly, suitable for simulating effects such as moving points over long distances; each port with a diameter of no more than 1 cm integrates dozens or hundreds of fiber optic channels.

[0028] The parameter adjustment range of the laser light source emitted to the multi-channel magnetically compatible optical fiber array 7 is: the laser wavelength is 1875nm, the laser radiation energy is 0.1-1.0J / cm 2 The width of each stimulation pulse is 0.25 milliseconds, the frequency is 100-400 Hz, and the duration of the pulse sequence can be adjusted as needed.

[0029] The multi-channel magnetically compatible optical fiber array 7 has excellent magnetic resonance compatibility, minimizing the impact on the imaging signal. Since the magnetization inhomogeneity is proportional to the difference in susceptibility coefficient between the implanted material and the biological tissue, in this design, the optical fiber material is high-purity silica, and the shell material used to fix the optical fiber and encapsulate the optical fiber is lead-free glass, both of which have weak magnetism, and the difference in magnetic susceptibility with biological tissue / water is less than 3ppm (part per million), belonging to the first type of magnetically compatible materials.

[0030] The fiber array port has good biocompatibility, and its contact with brain tissue will not cause local deformation or chemical reaction due to immersion in a wet environment or stimulation during the experiment. Silica-based nanoparticles have been widely used to connect or load biomolecules, functional particles, therapeutic agents, and contrast agents, so glass and optical fibers show good biocompatibility.

[0031] The density of stimulation channels is high enough to achieve a spatial resolution of functional column level (sub-millimeter). When designing the port, we closely arranged 10*10 optical fiber channels with a diameter of 220um on the end face of 2.2mm*2.2mm at most. In the cerebral cortex of different experimental animals and even humans, the scale of functional columns generally varies from 200-800um, so the spatial density of the port design can be adjusted or the channels can be used selectively to ensure accurate stimulation and intervention with the accuracy of the functional column scale.

[0032] The speed of switching between channels is fast enough to achieve dynamic stimulation paradigms of different speeds and accurate control of the duration of stimulation for each channel. After shooting and testing under an ultra-high-speed camera, the channel switching speed of the system is stabilized within 0.5ms, and the error of the stimulation duration of each channel compared with the preset duration of the program is within 3‰. Since the discharge duration of a single neuron is generally in the order of ten milliseconds, and the sampling frequency of conventional brain imaging methods (including magnetic resonance imaging, endogenous optical imaging, two-photon imaging, etc.) is within 100Hz, the switching speed of the system meets the time accuracy requirements of neural activity and signal acquisition.

[0033] Flexible control of stimulation image output. In order to minimize the complexity of the input device, the system uses a multi-level fiber optic switcher to control channel switching, so as to flexibly switch the laser output between channels, so as to achieve dynamic stimulation image output. If multiple channels are required to output simultaneously, it is only necessary to reduce the connection level of the fiber optic switcher and increase the number of lasers 6 at the input end.

[0034] Multi-level connections make it possible to control more laser output channels with limited lasers 6 and fiber optic switches, and switching channels through galvanometers can ensure that the output power of each channel is basically consistent based on the stable output power of the laser 6.

[0035] By using a multi-level connected fiber optic switching unit and a programmable micro-electric control board, it is possible to flexibly switch the continuous laser generated by a laser 6 between different channels of the fiber optic array to produce complex stimulation trajectories and patterns, so as to conduct in-depth research on neural stimulation and visual input brain-computer interfaces.

[0036] The core is a self-designed and customized multi-channel fiber array ( Figure 2-4 , three different types of stimulation ports), a flexible INS sequence setting is achieved through the array and the optical path switcher 4 based on the piezoelectric polarizer. The laser pulse emitted by the laser 6 is input into the switcher, and the deflection angle of the piezoelectric sensing polarizer in the optical path is controlled by a four-bit high-low level, corresponding to one of the nine output optical path channels of the switcher, thereby achieving nine-choice optical path switching output. Based on this, through a double-level switcher group, the maximum number of switchable channels in a single experiment can reach 81 (=9×9). If the number of switches and the connection level are increased, the theoretical maximum number of switchable channels can be increased ( Figure 5 ). Each output channel of the optical path switcher 4 is connected to each channel of the optical fiber array through the SMA905 standard optical fiber interface. The laser is transmitted to the surface of the animal brain in the magnetic resonance cavity through a 15-meter optical fiber bundle, thereby achieving precise stimulation and activation of the surface layer of the cerebral cortex.

[0037] Therefore, the present invention adopts the above-mentioned collective array type magnetically compatible infrared neural stimulation system, which can simultaneously conform to the distribution of functional columns in different brain regions of different experimental animals, so as to achieve efficient exploration of the connection between functional columns and modulation of specific functions.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A collective array type magnetically compatible infrared neural stimulation system, characterized in that: It includes a signal generator, the output end of the signal generator is connected to the input end of the trigger, the output end of the trigger is connected to the input end of the microcontroller, the output end of the microcontroller is connected to the input end of the optical path switch and the input end of the pulse modulator, the output end of the pulse modulator is connected to a laser, the laser emits a laser light source to the optical path switch, and the optical path switch emits the laser light source to a multi-channel magnetically compatible optical fiber array; The diameters of the stimulation ports with different spatial distributions in the multi-channel magnetically compatible optical fiber array are all no larger than 1 cm, and all are integrated with several optical fiber channels with a diameter of 220 μm; The parameter adjustment range of the laser light source emitted to the multi-channel magnetically compatible fiber array is: the laser wavelength is 1875nm, and the end output laser radiation energy of the multi-channel magnetically compatible fiber array is 0.1-1.0J / cm 2 , each stimulation pulse has a pulse width of 0.25 milliseconds and a frequency of 100-400 Hz; The channel switching speed in the multi-channel magnetically compatible optical fiber array is no more than 0.5 ms, and the error between the stimulation duration of each channel and the duration preset in the microcontroller program is no more than 3‰.

2. The collective array magnetically compatible infrared neural stimulation system according to claim 1, characterized in that: The optical fiber material of the multi-channel magnetically compatible optical fiber array is silicon dioxide, and the shell material used for fixing and encapsulating the optical fiber is lead-free glass.

3. The collective array type magnetically compatible infrared neural stimulation system according to claim 2, characterized in that: A multi-level fiber optic switch is used to connect and control channel switching.

4. The collective array magnetically compatible infrared neural stimulation system according to claim 1, characterized in that: The photoelectric switch is a photoelectric switch based on a piezoelectric polarizer.

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