Xintai Zhao

Signal Regeneration and Function Rebuilding Using Microelectronic Neural Bridge between Two Far-Separated Nervous Systems

This paper reviews at first the features of the present information techniques including the telephone, the television, the computer, and the body sensor network briefly. Then, the concept and the construction of microelectronic neural bridges (MENB) are discussed. A special animal experiment in which the signal regeneration and the function rebuilding were realized by using a MENB between two far-separated nervous systems is demonstrated. The applications of presented concept are prospected.

Neural signal sensing, transmission and functional regeneration on different toads’ bodies

The presence of neural signals is the most important feature of animals’ life. Monitoring, analysis and regeneration of neural signals are important for the rehabilitation of paralyzed patients. In this paper, the neural signal regeneration between the proximal and the distal end of an injured nerve is introduced. In the experiment a microelectronic module is used as a channel bridge. The regeneration of nerve signals is realized from one toad’s sciatic nerve to another’s. Corresponding neural signals and EMG were recorded and analyzed. It will be a reference to further study on the neural signals and the relationship between a neural signal and the muscle locomotion.

Effects of Microelectrode Array Configuration and Position on the Threshold in Electrical Extracellular Stimulation of Single Nerve Fiber：a Modeling Study

A transient flnite-element model has been presented to simulate extracellular potential stimulating in a neural tissue by a nonplanar microelectrode array (MEA). This model allows simulating the extracellular potential and transmembrane voltage by means of a single transient computation performed within single flnite element (FE) software. The difierential efiects of the conflguration and position of MEA in electrical extracellular stimulation are analyzed theoretically. 3-D models of single nerve flber and difierent MEA are used for the computation of the stimulation induced fleld potential, whereas a cable model of a nerve flbre is used for the calculation of the transmembrane voltage of the nerve flber. The position of MEA and the spacing of the microelectrodes are varied while mono-, bi-, tri-, and penta-polar MEAs are applied. The model predicts that the lowest stimulation voltage threshold is obtained in the stimulation with penta-polar MEA. Moreover, the relationships, which exist between the thresholds of the electrical extracellular stimulation and the parameters including position of the electrode array and the spacing of the microelectrodes in array, are studied and obtained.

Wavelet denoising, pattern recognition and correlation analysis of toad's neural signals

In order to determine the temporal points of action potentials in the neural signals and the correlation between neural signals, and to form an interface with the hardware system, a series of methods for signal denoising, pattern recognition, correlation analysis and primary signal coding are accepted. A set of toads neural signals are used as the experimental object. The results show that in combination with the wavelet technique, the method of pattern recognition is effective when non-stationary neural signals are processed, the correlation analysis could describe the relationship between signals,and signal coding could initially form a communication interface with the hardware system.

Surface myoelectric signals decoding using the continuous wavelet transform singularity detection

Electromyographic (EMG) signals are the resultant of electrical activity of muscle fibers during a muscle contraction, whose pattern can provide a significant reference of a motor rehabilitation system. The EMG decoding method using “refractory period” and “threshold” is appropriate for real-time processing system due to its low algorithm complexity and the good fidelity of time domain information. In this paper, the distribution of intervals between continuous wavelet transform modulus maxima was analyzed to provide a reasonable determination of the “refractory period”. In addition, the source signals were decoded according to the “refractory period”. Promising results are demonstrated.

Neural signal sensing from spinal cords and periphery nerves

This paper gives an introduction on the neural signal sensing of the system of microelectronic-embedded channel bridge and signal regeneration of injured spinal cords and periphery nerves. For neural signal sensing, electrode arrays of both cuff and needle types were used. For neural signal amplifying, the circuits realized with discrete devices and in CMOS process will be discussed. The application of the sensing circuits in a neural channel bridge system will be demonstrated.

EMG-signal regeneration and motor function rebuilding of paralyzed/anergic limbs based on communication principles and with RF-wireless technology

This work presents motor function rebuilding of paralyzed limbs of hemiplegic patients after stroke and anergic limbs of senile people. The biomedical methods and the traditional physical methods for rehabilitation of the paralyses are reviewed. The core part is to discuss EMG-signal regeneration and the limb function rebuilding based on communication principles and functional electrical stimulation-a novel concept developed by the speakers. For the EMG-signal transmission, different radio-frequency (RF) transmission systems are utilized. The construction of the whole bio-electronic system and the preliminary experiments on healthy patients are demonstrated.

The Principle of the Micro-Electronic Neural Bridge and a Prototype System Design

The micro-electronic neural bridge (MENB) aims to rebuild lost motor function of paralyzed humans by routing movement-related signals from the brain, around the damage part in the spinal cord, to the external effectors. This study focused on the prototype system design of the MENB, including the principle of the MENB, the neural signal detecting circuit and the functional electrical stimulation (FES) circuit design, and the spike detecting and sorting algorithm. In this study, we developed a novel improved amplitude threshold spike detecting method based on variable forward difference threshold for both training and bridging phase. The discrete wavelet transform (DWT), a new level feature coefficient selection method based on Lilliefors test, and the k-means clustering method based on Mahalanobis distance were used for spike sorting. A real-time online spike detecting and sorting algorithm based on DWT and Euclidean distance was also implemented for the bridging phase. Tested by the data sets available at Caltech, in the training phase, the average sensitivity, specificity, and clustering accuracies are 99.43%, 97.83%, and 95.45%, respectively. Validated by the three-fold cross-validation method, the average sensitivity, specificity, and classification accuracy are 99.43%, 97.70%, and 96.46%, respectively.

Neural signal regeneration and motor function rebuilding of paralyzed limbs based on principles of communication incorporated with microwave transmission system

In this presentation the motor function rebuilding of paralyzed limbs of the paraplegic patients caused by spinal cord injury and the hemiplegic patients after stroke and SCI is concerned. The biomedical methods and the traditional physical methods for the rehabilitation of two kinds of paralyses are reviewed. The core part is to discuss the neural and muscular signal regeneration and the limb function rebuilding based on the principles of communication and functional electrical stimulation - a novel concept developed by the speakers. For the communication, a microwave transmission system is incorporated. The construction of the whole bio-electronic system, the animal experiments, and the elementary experiments on healthy and paralyzed patients will be demonstrated.

Motor function rebuilding of limbs based on communication principle and electronic system

In this paper, we report our novel idea on the function rebuilding for hemiplegic limbs and the primary experiments. The main concept is to connect the control-lost nerves or neuromuscular junctions by using a multi-channel micro- electronic neural bridge (MENB), regenerate the nervous signal, and rebuild the motor functions of the related limb. Since the injured nervous system in stroke-related hemiplegia is located in the brain and difficult to be identified and operate on, we use another nervous system functioning as a new signal source to supply similar neural signals. In these cases, that means, two independent nervous systems are connected by a MENB. As preclinical experiments, we have made a series of tests on bodies of animals and healthy human. The principle, the system construction and the experimental results will be given.