An experimental platform for implantable brain-computer interface of restricted movement

Abstract

An experimental platform for implantable brain-computer interface of limited movement, comprising: a cooperative control module, which extracts the brain neuron signals of a limited rat through a microelectrode, pre-processes and extracts features of the neuron signals, analyzes and processes the movement information contained therein, converts the movement information into appropriate control instructions, and delivers the control instructions from Raspberry Pi to Arduino to control the corresponding actions of a machine rat made by the limited rat, so as to realize the movement control and sensing feedback between the limited rat and the machine rat; and an external control module, which is installed on the machine rat, and is used for carrying out epidural spinal cord electrical stimulation on the limited rat with partial movement function after incomplete spinal cord injury and combining with external equipment for rehabilitation training. The application can analyze and record the neuron signals of specific regions when the limited rat performs actions, which is helpful for in-depth analysis of the neuron activity characteristics and regulation mechanism of the limited rat.

Description

Technical Field

[0001] This invention relates to the field of brain-computer interface experimental platform technology, and in particular to an implantable brain-computer interface experimental platform for restricted movement. Background Technology

[0002] The reconstruction of motor function in amputees is a long-term research and exploration process. Because damaged nerve cells are difficult to regenerate, it is currently impossible to directly repair damaged nerve tissue from a purely biomedical perspective. Therefore, using prostheses to help rebuild motor function is one of the important research directions. Studies by Shoham et al. found that in spinal cord injury patients who had been paralyzed for many years, neurons in the motor cortex of the brain maintained activation similar to those in the normal brain when attempting limb movement. Coordinated limb movements in the human body are carried out under the precise control of the nervous system. Understanding the neural regulatory mechanisms requires long-term animal experiments before clinical research can be applied. Because rats are similar to humans in terms of body structure and drug response, they are often used as experimental subjects in research.

[0003] With the continuous development of implantable brain-computer interface (BCI) technology, the acquired brain information is more accurate and can directly reflect the characteristics of brain activity. In 2014, the BCI team at Zhejiang University pioneered an implantable BCI experiment on a human. An epileptic patient observed a "rock, paper, scissors" diagram on a screen while simultaneously performing the same actions with their fingers. A robotic arm beside the bed could synchronize the patient's finger movements with control commands generated from real-time decoded brain signals. Currently, there is no research platform suitable for biological mice to perform such neural interface experiments. Commercially available robotic mice lack overall structural flexibility and are mostly used for tasks that conform to their biological characteristics. For example, the pipe-clearing robotic mouse described in Chinese Patent 202210616143.X is designed based on the unique structure and habits of rats, whose claws and teeth are hard and adept at digging and burrowing. While this patent utilizes the biological characteristics of rats to solve the problem of time-consuming and laborious pipe-clearing devices, it does not meet the requirements for the degree of freedom of robotic mice in neural interface experiments. Summary of the Invention

[0004] To address the above problems, this invention proposes an implantable brain-computer interface experimental platform for restricted movement, the specific technical solution of which is as follows:

[0005] An implantable brain-computer interface experimental platform for restricted movement includes:

[0006] The collaborative control module extracts and records neuronal signals from the brains of restricted rats using microelectrodes. It preprocesses and extracts features from the neuronal signals, analyzes and processes the motion information contained within them, and converts it into appropriate control commands. The Raspberry Pi transmits control commands to the Arduino to control the robotic mouse to synchronize with the corresponding actions made by the restricted rat. The robotic mouse's sensory information is then fed back to the restricted rat via electrical stimulation through the Raspberry Pi, thus realizing motion control and sensory feedback between the restricted rat and the robotic mouse.

[0007] The control module is installed on the robotic mouse. For rats with limited motor function after incomplete spinal cord injury, the control module is used to perform epidural spinal cord electrical stimulation on the limited rats and combine it with external equipment for rehabilitation training. The control module records the neuronal signals generated by the limited rats in real time and evaluates the activity characteristics and regulatory mechanisms of neurons under the condition of injury.

[0008] Furthermore, the motor intention of the neurons in the brain of the restricted rat is decoded to control the robotic mouse to make corresponding head movements, upper limb movements and lower limb movements in sync with the motor intention of the restricted rat.

[0009] Furthermore, the robotic mouse includes a head assembly, limb assemblies, and a torso structure. The head assembly is equipped with servos to enable the robotic mouse's head to swing and extend / retract. The limb assembly includes a leg structure and a tail structure. The legs and shoulders of the leg structure are each equipped with servos for control. When the robotic mouse receives an Arduino control command, the servos in the shoulders and legs rotate, causing the thighs and calves to swing, thus enabling the leg structure to walk and run. The tail structure is equipped with servos to control the swinging of the robotic mouse's tail, maintaining the robotic mouse's balance during movement. The torso structure includes an upper bracket and a lower bracket. The upper bracket is used to fix the Raspberry Pi, and connection channels for the Raspberry Pi circuitry are provided on both sides of the upper bracket. The lower bracket is used to fix the Arduino, and connection channels for the Arduino circuitry are provided on both sides.

[0010] Furthermore, the external equipment includes a weight-loss support device and a treadmill training device. The weight-loss support device can provide different weight-loss values ​​according to the injury status of the restricted rat and fix the restricted rat. The treadmill training device can be placed directly below the weight-loss support device to provide the restricted rat with running training at a certain speed.

[0011] Furthermore, the running speed of the treadmill training device is 0-15 cm / s.

[0012] Beneficial effects of this invention:

[0013] (1) This invention can analyze and record the neuronal signals in specific regions of restricted rats when they perform actions, which helps to analyze the neuronal activity characteristics and regulatory mechanisms of restricted rats in depth.

[0014] (2) The weight loss support device for restricted rats in this invention can provide different weight loss values ​​according to their injury status. It can be used in conjunction with the treadmill training device to fix the restricted rats in a comfortable posture, restrict their movement, and facilitate the completion of the prescribed tasks by the experimental personnel.

[0015] (3) The robotic mouse of the present invention can generate control commands based on the real-time decoded neuronal signals of the corresponding parts of the restricted rat and synchronize the actions of the restricted rat. It can also replace the restricted rat for other experimental studies.

[0016] (4) The present invention feeds back the various information collected by the robotic mouse in performing the neural interface experimental task to the restricted rat in a timely manner to achieve closed loop.

[0017] (5) The present invention can perform neural signal recording and electrical stimulation experiments. By fixing the wires with a weight reduction support device, electrical stimulation is performed on the epidural spinal cord of rats, and the neural signals generated by the rat feedback are recorded in real time, which facilitates neural signal decoding. Attached Figure Description

[0018] Figure 1 This is a flowchart of the implantable brain-computer interface experimental platform for restricted rats according to the present invention.

[0019] Figure 2 This is a schematic block diagram of the brain-computer interface of the present invention.

[0020] Figure 3 This is a schematic diagram of the overall assembly of the present invention.

[0021] Figure 4 This is a schematic diagram of the overall structure of the robotic mouse of the present invention.

[0022] Figure 5 This is a schematic diagram of the weight reduction support device of the present invention.

[0023] In the diagram: 1. Restricted rat; 2. Robotic rat; 201. Head assembly; 202. Leg structure; 203. Tail structure; 204. Upper support; 205. Lower support; 206. Servo motor; 3. Weight reduction support device; 301. Base; 302. Guide rail; 303. Fixing frame; 304. Middle crossbeam; 305. Upper crossbeam; 306. Tension sensor; 307. Lead screw; 308. Lead screw pair; 309. Guide block; 310. Slide rod; 311. Connecting seat; 312. Spring; 313. Backrest plate; 314. Experimental clothing; 4. Treadmill training device; 5. Signal amplifier; 6. Signal display device; 7. Multi-channel constant current stimulator. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0025] like Figure 1 , 2 As shown, an implantable brain-computer interface experimental platform for restricted movement includes:

[0026] The collaborative control module extracts and records neuronal signals from the brain of restricted rat 1 in real time through microelectrodes. It preprocesses and extracts features from the neuronal signals, analyzes and processes the motion information contained therein, and converts it into appropriate control commands. The control commands are transmitted from the Raspberry Pi to the Arduino to control the robotic mouse 2 to synchronize with the corresponding actions made by restricted rat 1. The sensory information of the robotic mouse 2 is fed back to restricted rat 1 through electrical stimulation controlled by the Raspberry Pi, realizing motion control and sensory feedback between restricted rat 1 and robotic mouse 2.

[0027] The control module is installed on the robotic mouse 2. For rats 1 with limited motor function after incomplete spinal cord injury, the control module is used to perform epidural spinal cord electrical stimulation on the rats 1 and combine it with external equipment for rehabilitation training. The neuronal signals generated by the rats 1 are recorded in real time, and the activity characteristics and regulatory mechanisms of neurons under the damaged condition are evaluated.

[0028] like Figure 1 The diagram shows a flowchart of the implantable brain-computer interface experimental platform used for restricted rat 1. Using a Raspberry Pi and STM32 series control chip, a microelectrode array is used to acquire neuronal signals from restricted rat 1. These signals are processed by signal amplifier 5, analyzed, and displayed on signal display device 6. Feature information is extracted and analyzed. Based on the movement trajectory characteristics of restricted rat 1 and the reaction status of various brain regions, corresponding control commands are formed to basically synchronize the limb activities of restricted rat 1, thereby achieving control of the behavior of robotic rat 2. It can also replace restricted rat 1 for other experimental studies. Furthermore, for rat 1 that has been amputated and has nerve damage, requiring the installation of a prosthesis to reconstruct motor function, the collaborative control module can realize the motor control and sensor feedback between restricted rat 1 and robotic rat 2 (prosthesis). The control module uses an STM32 as the main control chip to control a multi-channel constant current stimulator 7 to electrically stimulate the epidural spinal cord of the restricted rat 1, and records the neuronal signals generated by the restricted rat 1 in real time, which facilitates the decoding of neuronal signals. For the restricted rat 1 with intact limbs, by extracting and recording the neuronal signals of the cerebral cortex of the restricted rat 1 in real time, and combining rehabilitation training to assess the activity characteristics and regulatory mechanisms of neurons under the damaged condition, the experimenters can select according to the condition of the restricted rat 1 and the experimental purpose, and thus obtain an implantable brain-computer interface experimental platform for restricted movement.

[0029] like Figure 2The diagram shows a brain-computer interface. The control design of the robotic mouse 2 uses a dual control board with a Raspberry Pi simulating the "brain" and an Arduino simulating the "spinal cord". The serial port of the Raspberry Pi is used to communicate with the Arduino, giving the robotic mouse 2 a powerful computing advantage to complete complex control operations. This allows it to be compatible with both Windows and Linux systems, making development more diverse and convenient. At the same time, the Raspberry Pi can solve the problem of having to re-upload every time a new operation is performed, which greatly consumes development time.

[0030] like Figure 2 , 3 As shown, the motor intention of the neurons in the brain of the restricted rat 1 is decoded so as to control the robotic rat 2 to make corresponding head movements, upper limb movements and lower limb movements in sync with the motor intention of the restricted rat 1.

[0031] The robotic mouse 2 is designed to resemble a biological mouse, with its hind limbs being relatively large and its angle controlled to simulate the sitting posture of a rat. Its forelimbs are smaller and can be used to grasp objects, making them more flexible.

[0032] The robotic mouse 2 includes a head assembly 201, limb assemblies, and a torso structure. The head assembly 201 is equipped with servo motors 206 to enable the robotic mouse 2's head to swing and extend / retract. The limb assembly includes a leg structure 202 and a tail structure 203. The legs and shoulders of the leg structure 202 are each equipped with servo motors 206 for control. When the robotic mouse 2 receives an Arduino control command, the servo motors 206 in the shoulders and legs rotate, causing the thighs and calves to swing, enabling the leg structure 202 to walk and run. The tail structure 203 is equipped with servo motors 206 to control the swing of the robotic mouse 2's tail, maintaining the robotic mouse 2's balance during movement. The torso structure includes an upper bracket 204 and a lower bracket 205. The upper bracket 204 is used to fix a Raspberry Pi, and connection channels for Raspberry Pi circuitry are provided on both sides of the upper bracket 204. The lower bracket 205 is used to fix an Arduino, and connection channels for Arduino circuitry are provided on both sides. The above settings shift the control of the robotic mouse 2 from the head to the torso, which facilitates the concentration of the center of gravity, the convenience of wiring, and the calibration of the gyroscope. The design of each part is reasonably simplified, and the balance is achieved by the gyroscope and the algorithm.

[0033] Specifically, microelectrodes extract neuronal signals from corresponding parts of the restricted rat 1. The head movement is used to study the neuronal signals of brain activity in the restricted rat 1 when the head is simulated as the restricted part. The robotic rat 2 performs swinging and stretching tasks according to the experimenter's requirements. The upper limb movement is used to study the neuronal activity signals of the upper limb of the restricted rat 1 when the upper limb is simulated as the restricted part. The robotic rat 2 performs touching tasks according to the experimenter's requirements. The lower limb movement is used to study the neuronal activity signals of the lower limb of the restricted rat 1 when the lower limb is simulated as the restricted part. The robotic rat 2 performs sitting, walking, or running tasks according to the experimenter's requirements.

[0034] like Figure 4 , 5 As shown, the external equipment includes a weight-loss support device 3 and a treadmill training device 4. The weight-loss support device 3 can provide different weight-loss values ​​according to the injury status of the restricted rat 1 and fix the restricted rat 1. The treadmill training device 4 can be placed directly below the weight-loss support device 3 to provide the restricted rat 1 with running training at a certain speed.

[0035] The weight reduction support device 3 includes a base 301, guide rails 302 mounted on both sides of the base 301, and a fixed frame 303 disposed on the top of the two guide rails 302. A middle crossbeam 304 is installed in the middle of the two guide rails 302, and an upper crossbeam 305 that can move up and down on the two guide rails 302 is installed on the upper part of the two guide rails 302. A servo motor is installed on one side of the middle of the upper crossbeam 305, and a tension sensor 306 is installed on the other side. A lead screw 307 is rotatably disposed in the middle of the fixed frame 303. A lead screw pair 308 connected to the lead screw is installed at the drive end of the servo motor, thereby using the servo motor to control the lead screw. The auxiliary beam 308 rotates to adjust the height of the upper crossbeam 305. A guide block 309 with a sliding groove is vertically mounted in the middle of the intermediate crossbeam 304. A sliding rod 310, movable within the sliding groove, is mounted at the bottom of the tension sensor 306. A connecting seat 311 is mounted on the sliding rod 310, and a spring 312 connected to the tension sensor 306 is provided on the connecting seat 311. An adjustable backrest plate 313 is hinged to the bottom end of the sliding rod 310, and strong Velcro fasteners are provided on the backrest plate 313. Wire clips are provided on both sides of the backrest plate for securing the leads of the neuronal signal recording and electrical stimulation device. The restricted rat 1 can wear an experimental garment 314, the back of which also has strong Velcro fasteners that can cooperate with the backrest, thereby allowing the restricted rat 1 to be comfortably secured in a fixed posture. The tension sensor 306 is used to measure the weight reduction provided by the weight reduction support device 3 to the restricted rat 1. During the training process of the restricted rat 1, if its center of gravity floats, the servo motor will rotate forward or backward according to the floating position of the center of gravity, and adjust the height of the spring 312 in real time to ensure that a constant weight reduction force is provided, so as to obtain accurate data in real time.

[0036] like Figure 3 As shown, the treadmill training device 4 can be used alone or in conjunction with the weight reduction support device 3. The treadmill training device 4 can be a conventional treadmill, and can also be used alone for other scientific research experiments to provide accurate experimental data.

[0037] The treadmill training device 4 includes at least a housing and an electric running track. The electric running track is installed inside the housing, and the housing is equipped with a speed-regulating motor. The speed-regulating motor is equipped with a transmission mechanism that can drive the electric running track. The electric running track includes at least a drive shaft, a driven shaft, and a running belt installed on it. The speed of the running belt is infinitely adjustable in the range of 0 to 15 cm / s. To prevent the running belt from deviating, the drive shaft and the driven shaft can be processed into a cone shape with a high middle and low sides.

Claims

1. An experimental platform for implantable brain-computer interface for restricted movement, characterized in that, include: The collaborative control module extracts and records neuronal signals from the brains of restricted rats using microelectrodes. It preprocesses and extracts features from the neuronal signals, analyzes and processes the motion information contained within them, and converts it into appropriate control commands. The Raspberry Pi transmits control commands to the Arduino to control the robotic mouse to synchronize with the corresponding actions made by the restricted rat. The robotic mouse's sensory information is then fed back to the restricted rat via electrical stimulation through the Raspberry Pi, thus realizing motion control and sensory feedback between the restricted rat and the robotic mouse. The control module is installed on the robotic mouse. For rats with limited motor function after incomplete spinal cord injury, the control module is used to perform epidural spinal cord electrical stimulation on the limited rats and combine it with external equipment for rehabilitation training. The control module records the neuronal signals generated by the limited rats in real time and evaluates the activity characteristics and regulatory mechanisms of neurons under the condition of injury.

2. The experimental platform for implantable brain-computer interface of restricted movement according to claim 1, wherein, The motor intention of neurons in the brain of restricted rats is decoded to control a robotic mouse to perform corresponding head movements, upper limb movements, and lower limb movements in sync with the motor intention of the restricted rats.

3. The experimental platform for implantable brain-computer interface of restricted movement according to claim 2, wherein, The robotic mouse includes a head assembly, limb assemblies, and a torso structure. The head assembly is equipped with servos to enable the head to swing and extend / retract. The limb assembly includes a leg structure and a tail structure. The legs and shoulders of the leg structure are each equipped with servos for control. When the robotic mouse receives an Arduino control command, the servos in the shoulders and legs rotate, causing the thighs and calves to swing, enabling the leg structure to perform walking and running movements. The tail structure is equipped with servos to control the swinging of the robotic mouse's tail, maintaining the robotic mouse's balance during movement. The torso structure includes an upper bracket and a lower bracket. The upper bracket is used to fix a Raspberry Pi, and connection channels for the Raspberry Pi circuitry are provided on both sides of the upper bracket. The lower bracket is used to fix an Arduino, and connection channels for the Arduino circuitry are provided on both sides.

4. The implantable brain-computer interface experimental platform for restricted movement according to claim 1, characterized in that, The external equipment includes a weight-loss support device and a treadmill training device. The weight-loss support device can provide different weight-loss values ​​according to the injury status of the restricted rats and fix the restricted rats. The treadmill training device can be placed directly below the weight-loss support device to provide the restricted rats with running training at a certain speed.

5. An implantable brain-computer interface experimental platform for restricted movement according to claim 4, characterized in that, The running speed of the treadmill training device is 0-15 cm / s.

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