Piezoelectric micro-driving device for synchronously recording electroencephalogram signals of multiple brain areas of rat at high precision

Abstract

The invention belongs to the technical field of precise driving and positioning, and relates to a high-precision piezoelectric micro-driving device for synchronously recording rat multi-brain-region neural signals, which mainly comprises a piezoelectric stack driving element, a thermal shrinkage and cold expansion material clamping element, a rectangular flexible hinge, a neural electrode and a packaging shell. The driving element can provide a stepping displacement output power source for the neural electrode, the clamping elements are embedded into an upper PCB and a lower PCB in pairs and can clamp and release the neural electrode, and the flexible hinge can regulate and control the stepping displacement output characteristic of the neural electrode. The piezoelectric micro-driving device independently translates a plurality of neural electrodes by cooperatively controlling a driving element and a clamping element under the excitation of a time sequence signal, and is accurately implanted into a target brain region of a rat to synchronously record neural signals of multiple brain regions. The device is simple and compact in structure, small and light, easy to integrate and miniaturize, capable of being used for accurate, independent and rapid micron-level positioning of multiple neural electrodes, and beneficial for achieving high-precision, multi-brain-area and large-scale synchronous recording of rat electroencephalogram signals.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision drive and positioning, and relates to a piezoelectric micro-drive device for high-precision synchronous recording of electroencephalogram signals in multiple brain regions of rats. Background Art

[0002] Brain-computer interface is a key core device in modern brain science research and an important research content of brain-computer intelligence technology in China's "China Brain Project". As a typical representative of brain-computer interface, implantable artificial neural electrodes are important tools for studying brain science and neuroscience and can collect high-quality electroencephalogram signals. On the one hand, electroencephalogram signals can be used for the principle research of the neural basis of cognitive functions, so as to reveal and understand the functions and activities of the brain. On the other hand, artificial neural electrodes can monitor and record neuronal electrical activities, extract various information about thinking, perception, movement and other cognitive functions from them, and are used for the research and treatment of neurological diseases such as epilepsy, Parkinson's disease and stroke, which is of great significance for the diagnosis, treatment and rehabilitation of major human brain diseases. Obtaining high-quality electroencephalogram signals through implantable artificial neural electrodes is the key to achieving the above-mentioned principle and application research goals of brain-computer interface, which not only relates to the comprehensive performance of artificial neural electrodes themselves, but also depends on the precise positioning of artificial neural electrodes during the implantation process in the brain.

[0003] In the field of brain-computer interface applications, the research on precise driving and positioning technologies for implantable artificial nerve electrodes is still in its infancy. According to different driving principles, at present, implantable artificial nerve electrode micro-drivers can be mainly divided into two types: manual driving type and electric driving type. The manual driving type micro-driver controls the movement of each independent nerve electrode based on the cooperation of a driving screw rod and a clamping element. Specifically, by manually rotating the driving screw rod, the clamping element installed on the screw rod is driven to move linearly by means of screw transmission, thereby driving the artificial nerve electrode to generate an output displacement. However, the manual driving type micro-driver has problems such as low positioning accuracy, poor stability, cumbersome and time-consuming operation, and low automation. The electric driving type micro-drivers mainly include two categories: electromagnetic type and piezoelectric type, which control the movement of artificial nerve electrodes based on the principles of electromagnetic induction and piezoelectric inverse effect respectively, promoting the rapid development of automated precision micro-driving and positioning technologies for implantable artificial nerve electrodes. However, the electromagnetic type micro-driver has significant electromagnetic interference, and although the piezoelectric type micro-driver has no electromagnetic interference, it still adopts the traditional piezoelectric inchworm driving mode - that is, each artificial nerve electrode requires the cooperation of a piezoelectric driving unit and two clamping units to achieve displacement output. At present, with the rapid development of brain science and neuroscience, the urgent need to collect high-quality, high-throughput electroencephalogram signals from multiple brain regions has led to the frequent use of an arrayed method to increase the number of nerve electrodes, which has doubled the number of driving units and clamping units of the piezoelectric micro-driver for transmission. The huge volume and weight are not conducive to the integration and miniaturization of the entire brain-computer interface system, greatly limiting the development of its clinical applications. On the other hand, in the field of brain-computer interface research, at present, a multi-channel electrode planar array implantation method is often used to obtain high-throughput electroencephalogram signals. However, the brain is a three-dimensional structure, and the distribution of neurons is uneven. The electrode array implantation method cannot achieve precise and efficient global positioning of neurons, and the increase in the number of electrodes will inevitably increase the potential risk of harm to some brain tissues. Therefore, how to achieve high positioning accuracy, high positioning efficiency, good safety, easy integration and miniaturization, and synchronous recording of neuron signals from multiple brain regions is the difficulty and focus of the current research on precise driving and positioning technologies for implantable artificial nerve electrodes. Summary of the Invention

[0004] The object of the present invention is to provide a piezoelectric micro-driving device for high-precision synchronous recording of electroencephalogram signals from multiple brain regions of rats, realizing the integration and miniaturization of the system, accurately and safely completing the independent precise implantation of artificial nerve electrodes in multiple brain regions of rats, efficiently and quickly positioning neurons, and synchronously recording high-throughput neuron signals from multiple brain regions.

[0005] The present invention mainly includes the top part (110) of the encapsulation housing, the middle part (120) of the encapsulation housing, the bottom part (130) of the encapsulation housing, PCBs (printed circuit boards) (210, 220), piezoelectric stack drive elements (300), rectangular flexible hinges (400), thermally shrinkable and cold-expandable material clamping elements (including but not limited to thermally shrinkable TPE elastomer materials, referring to all materials with thermally shrinkable and cold-expandable characteristics) (510, 520), nerve electrodes (600), lead tubes (700), and sleeves (800). The encapsulation housing is composed of three parts: the top part (110) of the encapsulation housing, the middle part (120) of the encapsulation housing, and the bottom part (130) of the encapsulation housing; the piezoelectric inchworm driver is composed of four parts: PCBs (printed circuit boards) (210, 220), piezoelectric stack drive elements (300), rectangular flexible hinges (400), and thermally shrinkable and cold-expandable material clamping elements (510, 520); the nerve electrode unit is composed of three parts: nerve electrodes (600), lead tubes (700), and sleeves (800).

[0006] The overall shape of the encapsulation housing is similar to a cuboid. There is a handle (111) above the top part (110) of the encapsulation housing for facilitating opening for inspection or disassembly of the micro-drive device. A tenon-like structure is provided below the top part of the encapsulation housing for connection with the middle part of the encapsulation housing; there are tenon grooves of a similar type on the upper and lower sides of the middle part (120) of the encapsulation housing for connecting the top and bottom of the housing. At the same time, through holes are provided on both sides of the upper part for cooperation with bolts and nuts (212); a tenon-like structure is also provided above the bottom part (130) of the encapsulation housing for connection with the middle part of the encapsulation housing. A rectangular opening is provided below the bottom part of the encapsulation housing for connection with the sleeve using glue. The remaining part of the bottom part of the encapsulation housing except for the part below connected to the sleeve is fixed on the rat skull using dental cement, so that the micro-drive device can operate stably without shaking when the rat is moving freely. The encapsulation housing is used to protect internal components such as the piezoelectric inchworm driver and nerve electrodes.

[0007] The piezoelectric inchworm actuator is installed in the encapsulation housing. The upper PCB (210) is fixed to the upper middle part of the encapsulation housing with angle steel and bolts. Above the upper PCB (210), an electric control system is arranged (including a central control chip, a stack drive chip, a coil heating chip, and a signal acquisition and processing unit. Among them, the central control chip is the core processing unit of the electric control system, responsible for executing and coordinating various calculations and control tasks. The stack drive chip controls the movement of the piezoelectric stack drive element. The coil heating chip controls the opening and closing of the clamping element. The signal acquisition and processing unit is connected to the nerve electrode for transmitting the collected electroencephalogram signals of the rat brain). The upper PCB is fixed to the upper end of the rectangular flexible hinge with bolts and nuts, and a pre-tightening force is applied to the piezoelectric stack drive element; the center line of the piezoelectric stack drive element is aligned with the center line of the through hole of the rectangular flexible hinge, and is fixedly installed inside the rectangular flexible hinge by the pre-tightening force provided by the bolt (223). Specifically, the bolt sequentially passes through the through hole on the top (110) of the encapsulation housing, the threaded through hole on the upper plate (210) of the PCB, and contacts the upper surface of the flexible hinge (300). By adjusting the screwing in of the bolt, a micro-movement generated along the working direction of the piezoelectric stack can be realized, thereby realizing the pre-tightening of the piezoelectric stack. The lower end of the rectangular flexible hinge is fixed to the lower PCB with bolts and nuts; The heat-shrinkable and cold-expandable material clamping elements are paired and embedded in the upper and lower PCBs. The periphery of the material is wrapped with heating coils (511, 521). Specifically, the heating coils are glued in the holes drilled in the upper and lower PCBs with epoxy resin, and the heat-shrinkable and cold-expandable material is filled into the gaps of the holes. Under the excitation of the sequential electric control signals output by the coil drive chip, each pair of clamping elements can perform clamping and releasing actions on the nerve electrode (600) wrapped with a lead tube (700) made of insulating material.

[0008] The rectangular flexible hinge (400) can play a role in amplifying or reducing the stepping displacement of the nerve electrode, improving the regulation ability and stepping accuracy of the stepping characteristics of the nerve electrode, thereby improving the positioning accuracy of the neuron cells and reducing the neuron damage during the brain tissue implantation process. The sleeve is used to gather the nerve electrodes and plays a protective role.

[0009] The lead tube (700) is made of insulating material, which is sleeved outside the nerve electrode, plays a protective role for the nerve electrode, prevents the nerve electrode from being damaged due to excessive clamping force of the clamping element, and also plays an insulating role to avoid the signal crosstalk problem of other nerve electrodes.

[0010] The nerve electrode (600) is a sheet-shaped silicon-based electrode, which is used to locate neurons, collect electroencephalogram signals, and the axon discharge of the captured neuron cells is the collected electroencephalogram signal. Each nerve electrode is provided with 8 acquisition sites, which increases the number of signal channels.

[0011] Furthermore, under the excitation of the stack driving signal, the telescopic movement of the piezoelectric stack driving element causes the rectangular flexible hinge to deform, which in turn drives the up-and-down linear movement of the lower PCB.

[0012] Furthermore, the coil heating chip outputs a timing signal to the coil. When the voltage is low, the heating coil is not energized, and the thermally shrinkable and cold-expandable material maintains a low-temperature expansion state, tightly wrapping the nerve electrode to play a clamping role. When the voltage is high, the heating coil is energized to heat, and the thermally shrinkable and cold-expandable material shrinks when heated, with a reduced volume. There is a gap between the thermally shrinkable and cold-expandable material and the nerve electrode, releasing the nerve electrode.

[0013] Furthermore, the central control chip outputs instructions to control the coil heating chip and the stack driving chip to simultaneously output different timing electro-control signals. In coordination with the telescopic movement of the piezoelectric stack driving element and the clamping / releasing actions of the clamping element, the driving element and the clamping element are synergistically controlled to independently translate multiple nerve electrodes, accurately implanting them into the target brain area of the rat to synchronously record the electroencephalogram signals of multiple brain regions. The signal acquisition and processing unit is connected to the nerve electrodes to record and capture the neuron signals collected by the nerve electrodes, and after preliminary processing of the neuron signals through operations such as amplification and filtering, it outputs them to the computer.

[0014] The present invention introduces a piezoelectric inchworm driver. Compared with the conventional nerve electrode driving devices in the past, the piezoelectric inchworm driver has higher precision and high stability, providing a higher spatial resolution for the movement of nerve electrodes. The multiple nerve signal acquisition sites at the end of the nerve electrode greatly improve the efficiency and stability of signal recording, meeting the needs of high-throughput and high-precision electroencephalogram signal acquisition in the current field of brain science. Through a piezoelectric stack driving element and multiple pairs of thermally shrinkable and cold-expandable material clamping elements, multiple nerve electrodes containing multiple detection sites are efficiently and independently implanted into specific brain regions, changing the multi-drive and multi-movement into one-drive and multi-movement, reducing the number of piezoelectric stack driving units. With the coordination of the timing electro-control signal, multiple nerve electrodes are simultaneously driven and controlled to synchronously record the nerve signals of multiple brain regions in the rat, and at the same time, the implantation time is reduced, the operation difficulty is lowered, the cost is reduced, and the stability and accuracy of electrode implantation are improved. Description of the Drawings

[0015] The present invention will be further described below in conjunction with the drawings and embodiments.

[0016] Figure 1 is a cross-sectional view of a piezoelectric micro-driving device for high-precision synchronous recording of electroencephalogram signals of multiple brain regions in rats according to the present invention.

[0017] Figure 2 is a schematic diagram of the piezoelectric micro-driving device of the present invention installed on the head of a rat.

[0018] Figure 3It is an exploded view of the structure of a piezoelectric micro-drive device for synchronously recording electroencephalogram signals from multiple brain regions of rats with high precision in the present invention.

[0019] Figure 4 It is the schematic diagram of the movement principle of the piezoelectric micro-drive device in the present invention.

[0020] The marks in the attached drawings are respectively noted as follows: Top of the encapsulation shell (110), handle (111), middle part of the encapsulation shell (120), bottom of the encapsulation shell (130), PCB (printed circuit board) (210, 220), angle steel (211), bolt and nut (212), electronic control system (213), bolt (221), bolt and nut (222), piezoelectric stack drive element (300), rectangular flexible hinge (400), heat shrinkage and cold expansion material (including but not limited to heat shrinkable TPE elastomer material, referring to all materials with the characteristics of heat shrinkage and cold expansion) clamping elements (510, 520), heating coils (511, 521), nerve electrodes (600), nerve electrode 1 (601), nerve electrode 2 (602), nerve electrode 3 (603), nerve electrode 4 (604), guiding tube (700), and sleeve (800). Specific embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the attached drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Figures 1 to 4

[0022] The embodiments of the present invention application provide a piezoelectric micro-drive device for synchronously recording electroencephalogram signals from multiple brain regions of rats with high precision. This micro-drive device is as Figures 1 to 3 shown. Figure 1 ​Shows a sectional view of the device of this embodiment, which includes the top of the encapsulation housing (110), the middle of the encapsulation housing (120), the bottom of the encapsulation housing (130), PCBs (printed circuit boards) (210, 220), piezoelectric stack drive elements (300), rectangular flexible hinges (400), heat-shrinkable and cold-expandable material clamping elements (including but not limited to heat-shrinkable TPE elastomer materials, referring to all materials with heat-shrinkable and cold-expandable characteristics) (510, 520), nerve electrodes (600), lead tubes (700), and sleeves (800). The encapsulation housing is composed of three parts: the top of the encapsulation housing (110), the middle of the encapsulation housing (120), and the bottom of the encapsulation housing (130); the piezoelectric inchworm driver is composed of four parts: PCBs (printed circuit boards) (210, 220), piezoelectric stack drive elements (300), rectangular flexible hinges (400), and heat-shrinkable and cold-expandable material clamping elements (510, 520); the nerve electrode unit is composed of three parts: nerve electrodes (600), lead tubes (700), and sleeves (800).

[0023] The overall shape of the encapsulation housing is similar to a cuboid and is composed of the top of the encapsulation housing (110), the middle of the encapsulation housing (120), and the bottom of the encapsulation housing (130), as Figure 3 (a) shows. There is a handle (111) above the top of the encapsulation housing (110) for facilitating opening for inspection or disassembly of the micro-drive device, and a tenon-like structure is provided below the top of the encapsulation housing for connection with the middle of the encapsulation housing; there is a tenon groove of a similar type at both the top and bottom of the middle of the encapsulation housing (120) to connect the top and bottom of the encapsulation housing; there is also a tenon-like structure above the bottom of the encapsulation housing (130) for connection with the middle of the encapsulation housing, and a rectangular opening is provided below the bottom of the encapsulation housing for connection with the sleeve (700) using glue; the rest of the part below the bottom of the encapsulation housing except for the part connected to the sleeve is fixed to the rat skull with dental cement, as Figure 2 shown, so that the micro-drive device can operate stably without shaking when the rat is moving freely. The encapsulation housing is used to protect internal components such as the piezoelectric inchworm driver and nerve electrodes.

[0024] The piezoelectric inchworm driver is composed of a single piezoelectric stack driving element, a plurality of pairs of heat-shrinkable and cold-expandable material (such as heat-shrinkable TPE elastomer material) clamping elements, upper and lower PCBs and a rectangular flexible hinge. The upper PCB (210) is fixed to the upper middle end of the package shell by angle steel and bolts, and an electric control system (including a central control chip, a stack drive chip, a coil heating chip and a signal acquisition processing unit) is arranged above the upper PCB, wherein the central control chip is the core processing unit of the electric control system and is responsible for executing and coordinating various calculation and control tasks, the stack drive chip controls the movement of the piezoelectric stack drive element, the coil heating chip controls the opening and closing of the clamping element, and the signal acquisition processing unit is connected to the neural electrode for transmitting the collected rat brain electrical signal), the upper PCB is fixed to the upper end of the rectangular flexible hinge by bolts and nuts, and a pre-tightening force is applied to the piezoelectric stack drive element; the center line of the piezoelectric stack drive element is aligned with the center line of the rectangular flexible hinge through-hole, and is fixedly installed inside the rectangular flexible hinge by the pre-tightening force provided by the bolts (221), and the lower end of the rectangular flexible hinge is fixed to the lower PCB by bolts and nuts, and the coil heating chip is arranged below the lower PCB and is connected and communicated with the central control chip of the upper PCB board by a flexible flat cable. The heat shrinkable and cold expansion material clamping elements are embedded in pairs in the upper and lower PCBs, and the material wraps around the heating coil. Specifically, the heating coil is glued to the holes punched in the upper and lower PCBs with epoxy resin, and the heat shrinkable and cold expansion material fills the gaps in the holes. Under the stimulation of the timing electric control signal output by the coil driving chip, each pair of clamping elements can clamp and release the neural electrode wrapped with the guide tube made of insulating material.

[0025] The neural electrode (600) is a sheet-shaped silicon-based electrode used to locate neurons and collect brain electrical signals. The captured neuron cell axon discharge is the collected brain electrical signal. Each neural electrode is provided with 8 collection sites, thereby increasing the number of signal channels. The guide tube (700) is made of an insulating material, which is sheathed on the outside of the neural electrode and fixed with glue, thereby protecting the neural electrode and preventing the clamping element from damaging the neural electrode due to excessive clamping force. It also serves as an insulator to avoid signal crosstalk.

[0026] Figure 4 The schematic diagram of driving a single nerve electrode and multiple nerve electrodes is shown. (a) shows the three stepping states of a single nerve electrode: (1) stepping down; (2) stepping up; (3) staying still. In the initial state, the stack driver chip outputs a low level to the piezoelectric stack driver element, and the coil heating chip outputs a low level to heating coil 1 and heating coil 2, so the piezoelectric stack driver element maintains its initial length. The three stepping states of a single electrode are described below: (1) Step down t0 - t1: The coil heating chip outputs a high level to heating coil 1 and maintains a low level for heating coil 2. Then, the temperature of heating coil 1 rises. The thermally expandable and contractible material inside the coil heats up accordingly, and the material contracts. The upper clamping element releases the nerve electrode. Heating coil 2 remains at a low temperature, and the thermally expandable and contractible material inside it also remains at a low temperature. The thermally expandable and contractible material expands when cooled and presses on the nerve electrode. Therefore, the lower clamping element clamps the nerve electrode. At the same time, the stack driver chip outputs a high level to the piezoelectric stack driving element. The piezoelectric stack driving element elongates under the signal excitation, causing the rectangular flexible hinge to deform and generate displacement, driving the lower - side PCB to move downward, and the nerve electrode steps downward under the clamping action.

[0027] t1 - t2: The coil heating chip outputs a low level to heating coil 1 and a high level to heating coil 2. Then, heating coil 1 cools down. The thermally expandable and contractible material inside the coil cools down accordingly, and the material expands. The upper clamping element clamps the nerve electrode. Heating coil 2 heats up, and the thermally expandable and contractible material inside it heats up accordingly, and the material contracts, releasing the nerve electrode. At the same time, the stack driver chip outputs a low level to the piezoelectric stack. The piezoelectric stack returns to its original length, the rectangular flexible hinge returns to its original state, the lower - side PCB moves upward, and the electrode remains stationary.

[0028] In summary, the nerve electrode moves downward one step in one cycle. Repeating the above steps can achieve continuous downward stepping of the nerve electrode.

[0029] (2)Upward stepping t0 - t1: The coil heating chip outputs a low level to heating coil 1 and a high level to heating coil 2. Then, the thermally expandable and contractible material inside heating coil 1 remains at room temperature, and the upper clamping element clamps the nerve electrode. Heating coil 2 heats up, and the thermally expandable and contractible material inside it heats up accordingly, and the material contracts, releasing the nerve electrode. At the same time, the stack driver chip outputs a high level to the piezoelectric stack. The piezoelectric stack elongates under the signal excitation, causing the deformation of the rectangular flexible hinge, generating displacement, driving the lower - side PCB to move downward, and the electrode remains stationary.

[0030] t1 - t2: The coil heating chip outputs a high level to heating coil 1 and maintains a low level for heating coil 2. Then, the temperature of heating coil 1 rises. The thermally expandable and contractible material inside the coil heats up accordingly, and the material contracts, releasing the nerve electrode. The thermally expandable and contractible material inside heating coil 2 remains at room temperature, and the lower clamping element clamps the nerve electrode. At the same time, the stack driver chip outputs a low level to the piezoelectric stack. The piezoelectric stack returns to its original length, the rectangular flexible hinge returns to its original state, driving the lower - side PCB to move upward, and the nerve electrode steps upward under the clamping action.

[0031] In summary, the nerve electrode moves upward one step in one cycle. Repeating the above steps can achieve continuous upward stepping of the nerve electrode.

[0032] (3)Keep still t0 - t1: The coil heating chip outputs a low level to the heating coil 1 and a high level to the heating coil 2. Then, the thermo - expansion - contraction material in the heating coil 1 remains at room temperature, and the upper clamping element clamps the neural electrode; the temperature of the heating coil 2 rises, and the thermo - expansion - contraction material in the coil heats up and contracts, releasing the neural electrode. At the same time, the stack - drive chip outputs a high level to the piezoelectric stack. The piezoelectric stack elongates under the signal excitation, causing the deformation of the rectangular flexible hinge and driving the lower - side PCB to move downward, while the electrode keeps still.

[0033] t1 - t2: The coil heating chip outputs a low level to the heating coil 1 and a high level to the heating coil 2. Then, the thermo - expansion - contraction material in the heating coil 1 remains at room temperature, and the upper clamping element clamps the neural electrode; the temperature of the heating coil 2 rises, and the thermo - expansion - contraction material in the coil heats up and contracts, releasing the neural electrode. At the same time, the stack - drive chip outputs a low level to the piezoelectric stack. The piezoelectric stack returns to its original length, the rectangular flexible hinge returns to its original state, the lower - side PCB moves upward, and the electrode still keeps still.

[0034] Similarly, the synchronous driving and control of multiple neural electrodes (taking 4 neural electrodes as an example) by the device proposed in this example are described as follows, as Figure 4 (b) shown: In the initial state, both the stack - drive chip and the coil heating chip output low levels. The piezoelectric stack remains at its original length, and the clamping elements all clamp the neural electrodes, achieving power - off self - locking to ensure safety.

[0035] t0 - t1: The coil heating chip outputs a low level to heating coil 1, a high level to heating coil 2, a low level to heating coil 3, a low level to heating coil 4, a high level to heating coil 5, a low level to heating coil 6, a low level to heating coil 7, and a high level to heating coil 8. Then, clamping element 1 (composed of heating coil 1 and a material that shrinks when heated and expands when cooled, the same below) clamps the nerve electrode, clamping element 2 (composed of heating coil 2 and a material that shrinks when heated and expands when cooled, the same below) releases the nerve electrode, clamping element 3 (composed of heating coil 3 and a material that shrinks when heated and expands when cooled, the same below) clamps the nerve electrode, clamping element 4 (composed of heating coil 4 and a material that shrinks when heated and expands when cooled, the same below) clamps the nerve electrode, clamping element 5 (composed of heating coil 5 and a material that shrinks when heated and expands when cooled, the same below) releases the nerve electrode, clamping element 6 (composed of heating coil 6 and a material that shrinks when heated and expands when cooled, the same below) clamps the nerve electrode, clamping element 7 (composed of heating coil 7 and a material that shrinks when heated and expands when cooled, the same below) clamps the nerve electrode, clamping element 8 (composed of heating coil 8 and a material that shrinks when heated and expands when cooled, the same below) releases the nerve electrode; At the same time, the stack drive chip outputs a high level to the piezoelectric stack drive element, and the piezoelectric stack elongates under the signal excitation, causing the rectangular flexible hinge to deform and generate displacement, driving the lower PCB to move downward, making the lower PCB move downward. At this time, nerve electrode 1 remains stationary, nerve electrode 2 remains stationary, nerve electrode 3 steps downward, and nerve electrode 4 remains stationary.

[0036] t1 - t2: The coil heating chip outputs a low level to heating coil 1, a high level to heating coil 2, a high level to heating coil 3, a low level to heating coil 4, a low level to heating coil 5, a high level to heating coil 6, a low level to heating coil 7, and a high level to heating coil 8. Then, clamping element 1 clamps nerve electrode 1, clamping element 2 releases nerve electrode 1, clamping element 3 releases nerve electrode 2, clamping element 4 clamps nerve electrode 2, clamping element 5 clamps nerve electrode 3, clamping element 6 releases nerve electrode 3, clamping element 7 clamps nerve electrode 4, clamping element 8 releases nerve electrode 4; At the same time, the stack drive chip outputs a low level to the piezoelectric stack, the piezoelectric stack returns to its original length, the rectangular flexible hinge returns to its original state, driving the lower PCB to move upward. At this time, nerve electrode 1 remains stationary, electrode 2 steps upward, electrode 3 remains stationary, and electrode 4 remains stationary.

[0037] In summary, the neural electrode 1 remains stationary, the electrode 2 steps upward, the electrode 3 steps downward, and the neural electrode 4 remains stationary. To add neural electrodes, only the number of pairs of clamping elements needs to be increased. Each neural electrode can output 8 channels of neuron signals, and multiple electrodes can synchronously collect neuron signals from multiple brain regions of the rat. The neural electrodes are connected to the signal acquisition and processing unit through a flexible cable, and the collected neuron signals are preprocessed (filtered, amplified, etc.) and input into the computer to complete the synchronous recording of high-precision rat neural signals.

[0038] In summary, in cooperation with the Figure 4 (a) timing signal, the control of 4 neural electrodes can be realized simultaneously within one device. These 4 neural electrodes respectively achieve three motion states: (1) stepping downward, (2) stepping upward, and (3) remaining stationary. Under the control of the timing electro-control signal, the micro-driving device can achieve continuous stepping motion and has the advantage of a large stroke. In theory, the number of clamping units and neural electrodes can be increased infinitely. By sending different timing electro-control signals to each coil, the synchronous control of multiple neural electrodes can be realized. In cooperation with signal processing and transmission, the synchronous recording of electroencephalogram signals from multiple brain regions of multiple target neural electrode rats can be realized. In addition, this technology can also significantly shorten the implantation time, reduce the operation difficulty and cost, and improve the stability and accuracy of electrode implantation, greatly increasing the efficiency and safety of rat electroencephalogram signal acquisition. This provides a useful idea for the miniaturization and integration of neural electrode drivers.

Claims

1. A piezoelectric micro-drive device for synchronously recording electroencephalogram signals of multiple brain regions in rats, mainly including the top of the encapsulation housing (110), the middle of the encapsulation housing (120), the bottom of the encapsulation housing (130), PCBs (printed circuit boards) (210, 220), a piezoelectric stack drive element (300), a rectangular flexible hinge (400), heat-shrinkable and cold-expandable material clamping elements (510, 520) (including but not limited to heat-shrinkable TPE elastomer materials, referring to all materials with heat-shrinkable and cold-expandable characteristics), nerve electrodes (600), a guiding tube (700), and a sleeve (800).

2. A piezoelectric micro-drive device for accurately synchronously recording electroencephalogram signals of multiple brain regions of rats according to claim 1, characterized in that: The top of the encapsulation housing (110), the middle of the encapsulation housing (120), and the bottom of the encapsulation housing (130) together constitute the encapsulation housing part of the piezoelectric micro-drive device. There is a tenon-like structure for connecting to the middle of the encapsulation housing. The middle of the encapsulation housing (120) has a groove on each of the upper and lower sides to connect the top and bottom of the encapsulation housing. The bottom of the encapsulation housing (130) also has a tenon-like structure above it for connecting to the middle of the encapsulation housing. There is a rectangular opening below the bottom of the encapsulation housing, which is connected to the sleeve (800) with glue. The sleeve is used to gather the nerve electrodes and plays a protective role. The rest of the part below the bottom of the encapsulation housing except the part connected to the sleeve is fixed to the rat skull with dental cement, so that the micro-drive device can operate stably without shaking when the rat is moving freely.

3. A piezoelectric micro - drive device for accurately synchronously recording electroencephalogram signals of multiple brain regions of rats according to claim 1, characterized in that: Inside the encapsulation housing, the upper-side PCB (210) is fixed to the upper end of the middle of the encapsulation housing with angle steel (211) and bolts and nuts (212). Above the upper-side PCB (210), an electric control system (213) is arranged (including a central control chip, a stack drive chip, a coil heating chip, and a signal acquisition and processing unit. Among them, the central control chip is the core processing unit of the electric control system, responsible for executing and coordinating various calculations and control tasks. The stack drive chip controls the movement of the piezoelectric stack drive element. The coil heating chip controls the opening and closing of the clamping elements. The signal acquisition and processing unit is connected to the nerve electrodes for transmitting the electroencephalogram signals of the rats collected); the center line of the piezoelectric stack drive element (300) is aligned with the center line of the through-hole of the rectangular flexible hinge, and is fixedly installed inside the rectangular flexible hinge by the pre-tightening force provided by bolts (221). Both the upper and lower ends of the rectangular flexible hinge are respectively fixed to the upper and lower-side PCBs (210, 220) with bolts and nuts (222); the heat-shrinkable and cold-expandable material clamping elements (510, 520) are paired and embedded in the upper and lower two PCBs (210, 220), and the periphery of the heat-shrinkable and cold-expandable material is wrapped with heating coils (511, 521); among them, the PCBs (printed circuit boards) (210, 220), the piezoelectric stack drive element (300), the rectangular flexible hinge (400), and the heat-shrinkable and cold-expandable material clamping elements (510, 520) together constitute a piezoelectric inchworm driver; the heat-shrinkable and cold-expandable material clamping elements clamp a guiding tube (700) made of insulating material, and the guiding tube is sleeved outside the nerve electrode, playing a protective and insulating role for the nerve electrode; each nerve electrode has 8 acquisition sites for collecting electroencephalogram signals.

4. A piezoelectric micro-drive device for accurately synchronously recording electroencephalogram signals of multiple brain regions of a rat according to claim 1, characterized in that: When the coil heating chip outputs a low level, the coil is powered off, and the thermally expandable and contractible material in the clamping element is at room temperature, and it expands when cooled to wrap the nerve electrode to play a clamping role; when the coil heating chip outputs a high level, the coil is powered on, and the thermally expandable and contractible material in the clamping element is in a heated state, and it shrinks when heated to release the nerve electrode to play a releasing role, that is, each pair of clamping elements can perform clamping and releasing actions on a single nerve electrode; based on the piezoelectric inchworm drive principle, combined with the above clamping / releasing mechanism, under the excitation of a timing electric control signal, the downward stepping movement, upward stepping movement and static holding of a single nerve electrode can be realized; when the piezoelectric micro-drive device is working, fix the bottom of its encapsulation shell on the rat skull, and the central control core issues instructions to control the piezoelectric stack drive chip and the coil heating chip at the same time, and outputs continuous timing signals to the piezoelectric stack and multiple heating coils. With the cooperation of multiple timing signals, a single drive unit can be used to realize the drive control of multiple nerve electrodes, independently and precisely implant them into the target brain area, and synchronously collect and record the electroencephalogram signals of multiple brain regions and large-scale brain regions of the rat.

Images