| Neuroprosthetics, also called neural prosthetics, is a discipline related to neuroscience and biomedical engineering concerned with developing neuroprosthetics. Cortical Neuroprosthetic are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. The cortical prosthesis by micro-electrical stimulation through dura mater aimed special neural function restoration, where the micro- electrode and functional integrated circuit is implanted on special dura mater of subject to stimulate the target neural tissue for the unblocked neural path, which is damaged by injury or disease. The advantage is minimally invasive, brain integrity and low-risk of infection.The proposed dissertation firstly analyzed the significance, concept and classification of neuroprosthetics, followed by the key technology and current research situation of neuroprosthetics. Then the dissertation summarized the concept of the cortical prosthesis by micro-electrical stimulation through dura mater, followed by its basic structure, current research situation and difficulties, finally the key technologies of the cortical prosthesis by micro-electrical stimulation through dura mater were elicited. After that inductive wireless power harvesting system, the wireless power harvesting telemetry system and wireless acquisition system in the cortical prosthesis by micro-electrical stimulation through dura mater were studied through system design and experiment. Further the animal experiment for verifying the feasibility of the cortical prosthesis by micro-electrical stimulation through dura mater has been carried out. The main research work is followed:1. A micro and high quality wireless power device is a necessary part for implanted circuit chip in the cortical prosthesis by micro-electrical stimulation through dura mater. The proposed paper designed a wireless power transmission system to meet the power supply demand of the cortical prosthesis by micro-electrical stimulation through dura mater. The proposed system includes extracorporeal power transmitter circuit and internal power receiver circuit, which is wireless connected each other by one pair of inductive coils. The extracorporeal part means the power transmitter circuit, which includes RF oscillator, class E amplifier and extracorporeal coil et al. The internal part is the power receiver circuit, which are rectifier, filter and regulator circuit. The Pspice simulation debug of the whole wireless power transmission circuit, CAD design and CAD layout of the wireless power receiver circuit have been accomplished. Further the test experiment of wireless power transmission has been done. The features of the proposed system are: the receiver circuit of wireless power supply outputs 3.3V, with CAD layout size as 62μm×195μm; the test experiment is finished by using the VLSI chip of Johns Hopkins University Neuroengineering & Biomedical Instrumentation Lab, and the system can output 3.3V 10mA within the distance of (10～15)mm in 4MHz carrier for the implanted circuit chip; The system is safe, stable and efficient for the cortical prosthesis by micro-electrical stimulation through dura mater, without external wire connected, battery and infection danger; the system provided a reliable tool of wireless power supply for further research of the cortical prosthesis by micro-electrical stimulation through dura mater.2. Not only the external power supply but also the extracorporeal electrical stimulus supply is needed when the implanted circuit chip of cortical prosthesis by micro-electrical stimulation through dura mater excuted special nerve function restoration. The proposed dissertation designed a VLSI wireless power harvesting telemetry system to accomplish the task for the cortical prosthesis by micro-electrical stimulation through dura mater. The system includes extracorporeal power transmitter and telemetry transmitter,internal power receiver and telemetry receiver. The schematic design of VLSI wireless power harvesting telemetry system is accomplished, and experiment platform was built and test experiment of wireless power harvesting telemetry based on inductive coils has been carried out. The highest baud rate, the optimized implanted inductive coil have been studied at the same time that output voltage of wireless power supply is stable. The features of the proposed system are followed. The power and data have been transmit in the same direction synchronously by one pair of inductive coil, and the experiment has been accomplished by using the VLSI chip and platform in Johns Hopkins University Neuroengineering & Biomedical Instrumentation Lab. The system can transmit the electrical stimulus data by 25kbps by implanted coil of 10mm radius within the distance of (10～15)mm at 4 MHz carrier for implanted circuit chip. The proposed wireless power harvesting telemetry technology is noninvasive, efficient telemetry method without external wire connected and infection danger.3. The cortical prosthesis by micro-electrical stimulation through dura mater is used for nerve function restoration not damage nerve tissue, which is guaranteed to be executed efficiently by monitoring the electrode-tissue interface of neuroprosthetics. In this paper a VLSI wireless acquisition system for Spike and EEG signal was designed to carry out the monitoring task. The proposed system includes 16-channel signal acquisition VLSI chip, RF transceiver chip and PC et al. The wireless acquisition system schematic of neuroprosthetic electrode-tissue interface information is put forward, the acquisition system is built, and the system performance test and vitro physiological signal wireless transmission experiment have been accomplished. The characteristic of this system are followed. The proposed system is portable with size of 56mm×50mm×30 mm. The proposed system makes use of 16-channel VLSI neuropotential acquisition chip, of adjustable parameter, low-dissipation and integration. The system can communicate the signal similar to Spike and EEG at 57.6kbps within the distance of one meter with BER lower than 8.9336×10-4. The wireless acquisition technology is one key technology and monitoring tool for the cortical prosthesis by micro-electrical stimulation through dura mater, because the proposed system can acquire the electrode-tissue interface information of neuroprosthetics for guaranteeing the nerve function restoration of the cortical prosthesis by micro-electrical stimulation through dura mater.4. The hypothesis of the cortical prosthesis by micro-electrical stimulation through dura mater is that the final electrical stimulus on the target cortex is still effective after it has transmit from the target dura mater. So the proposed paper designed a cat experiment of electrode-tissue interface in the cortical prosthesis by micro-electrical stimulation through dura mater to verify the hypothesis. The animal experiment schematic of electrode-tissue interface in the cortical prosthesis by micro-electrical stimulation through dura mater was put forward, the animal experiment platform was built, and tentative exploration of stimulus effective transmission from dura mater to cortex has been carried out. The main content is followed. The paper especially studied the electrical stimulus attenuation of the dura mater, cerebrospinal fluid (CSF) and pia mater. The experiment studied stimulus parameters effect in the transmission of electrical stimulus in the cortical prosthesis by micro-electrical stimulation through dura mater, which includes stimulus waveshape, pulsewidth and amplitude of single square current, record space sites. The scheme feasibility of the cortical prosthesis by micro-electrical stimulation through dura mater has been verified, which also settled experimental basis for further research of the cortical prosthesis by micro-electrical stimulation through dura mater.The proposed dissertation has carried out further study on the cortical prosthesis by micro-electrical stimulation through dura mater, which includes wireless power supply technology,VLSI wireless power harvesting telemetry technology and VLSI wireless acquisition technology. And animal experiment of schematic feasibility in the cortical prosthesis by micro-electrical stimulation through dura mater has been accomplished. The research and experiment in the paper has established substantial theory and experiment basis for further research on the cortical prosthesis by micro-electrical stimulation through dura mater. The creative work is summarized.(1) The paper put forward a method of transcranium wireless power supply and transcranium neural electrical stimulus transmission based on VLSI, and the circuit module both inductive wireless power receiver circuit based on VLSI and transcranium neural electrical stimulus transmission circuit based on Electromagnetic induction have been designed, especially the modification of low-drop regulator circuit and the transcranium neural electrical stimulus wireless transmission experiment through the coupling coils. The system can output 3.3V 10mA within the distance of (10～15)mm in 4MHz carrier for the implanted circuit chip, and it can transmit the electrical stimulus data by 25kbps.(2) The paper proposed a method of neural electrical signal wireless acquisition in the cortical prosthesis by micro-electrical stimulation through dura mater based on VLSI, and the wireless transcranium acquisition system has been developed, and the performance test of the system has been accomplished. It can communicate the signal similar to Spike and EEG at 57.6kbps within the distance of one meter with BER lower than 8.9336×10-4.(3) The paper proposed a method of electrode-tissue interface animal experiment in the cortical prosthesis by micro-electrical stimulation through dura mater, and animal experiment platform has been built, and tentative exploration of stimulus effective transmission from dura mater to cortex has been carried out, especially the scheme feasibility of the cortical prosthesis by micro-electrical stimulation through dura mater has been accomplished. |
PDF Full Text Request