Spatial Properties Of Electrically Evoked Potentials Elicited By Penetrative Stimulation Of Opitc Nerve

The research of using visual prosthesis based on electrical stimulation to restore vision for the blind has received a world-wide interest. Our research group proposed a novel visual prosthesis based on optic nerve stimulation with penetrating micro-electrode array. Based on demonstrating the feasibility and validity of this new type of optic nerve visual prosthesis, spatial properties of the electrically evoked potential (EEP) elicited by penetrating stimulation in optic nerve were investigated in this study.Main contents of this research include: the investigation of the visual system of the animal model; the construction of electrophysiological platform and the fabrication of the stimulating and recording electrodes; the investigation of the spatial properties of the EEP; the temporal differentiability of the EEP. The results in this study indicated that the spatial distributions of EEP in visual cortex demonstrated distinctively different properties when different stimulated site or stimulation mode (monopolar and bipolar) were used. The electrode pair parallel inserted into the temporal optic nerve could elicit a distinguished EEP using relatively lower stimulus intensity and provide appropriate spatial selectivity. The interval of the two continuous stimulating pulses should be set larger than 30ms for the visual cortex to differentiate them.The novelty of this research is the first time of investigating the spatial properties of the EEPs under the monopolar and bipolar electrical stimulation mode applied to the optic nerve, which can provide experimental data for the design of the electrical stimulation mode of the optic nerve visual prosthesis.