Research On The Influence Of 3d Electric Field On The Excitability Of The Optic Nerve

Vision is necessary for human to get information form the world. However, over 180 million people are visually impaired, including 45 million blind. Therefore, study on visual prosthesis is in an urge by the whole society. A lot of research groups have been making efforts to develop visual prosthesis and some progress has been made. Optic nerve stimulation with penetrating microelectrode array has been suggested as a possible and novel method for visual prosthesis. Simulating the neuron and neural network by mathmetical modeling and comperter simulation has become an important research method. So simulating the optic nerve stimulation with microelectrodes by using modeling methods, exploring the response properities, is of great importance to the study of optic nerve prosthesis.This paper focuses on the study of simulation of the optic nerve stimulation with penetrating microelectrodes. Simulation results can be used to reveal the electrophysiological mechanism of response properties of penetrative optic nerve stimulation, providing useful simulation data for optic nerve prosthesis.Main contents of this paper include: 1. Analyse different neuron modeling methods, model the optic nerve fiber exactly using double layer cable multicompartmental model as the modeling method and NERUON software as the simulation tool. 2. Implement a geometrically realistic finite element electrical model of penetraing microelectrodes by using Maxwell 3D software as the simulation tool. 3. Combine Maxwell and NEURON effectivly, carray out the simulation of the optic nerve stimulation with penetrating microelctrodes. 4. Carry on plenty of simulations of penetrative optic nerve stimulation, examine different response properties by extracellular point electrode stimulation, finite element simulated monopolar stimulation and finite element simulated bipolar stimulation. 5. Analyse and discuss the simulation results. The results suggest that cathoic and anodic stimulitions have different effects on the generating of the action potential, changes of stimulation location, electrode structure, electrodes layout pattern, electrodes separation, and stimulus pattern all can influnce the stimulus therholds.The novelties of this paper are modeling the optic nerve fiber exactly using double layer cable multicompartmental model for the first time, taking all the possible ion channels into account, simulating the extracelluare electric field more exactly by using the finite element software. Our optic nerve model is more complete then those in previous studies. By simulating the optic nerve stimulation with penetrating microelectrodes, we can provide theoretical guidance in designing the microelectrodes and stimulus strategies.