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O. R. Ziv, J. F. Rizzo, III; Multielectrode Recording of Responses From Retinal Ganglion Cells to Photic Stimuli of Variable Area and Electric Current Stimuli of Variable Magnitude. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4575.
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© ARVO (1962-2015); The Authors (2016-present)
This work is related to the efforts of the Boston Retinal Implant Project to develop a sub-retinal prosthesis to restore vision to the blind. The specific purpose of this presentation is to demonstrate a method to better understand the population responses of retinal ganglion cells (RGCs) to various sizes of photic stimuli, and compare it to various amplitudes of current stimuli, using a multielectrode array. The goal is to better understand the responses of RGCs to light and current stimulation in order to mimic these responses electrically by a retinal prosthesis.
Extracellular recordings of action potentials of RGCs were made in superfused New Zealand White rabbit retinas using a multielectrode array. The cells were stimulated by flashes of light at different radii, and by electric current at different magnitude. The photic stimulus duration was 0.5sec, and the electric current duration was 1 msec bi-phasic. The data collected at the different recording electrodes were analyzed by dedicated software to sort the action potentials and measure temporal and spatial parameters of the responses.
Recordings were obtained from variety of RGC’s. The responses of these cells to light flashes included onset, offset, or both responses for cells at different distances from the edge of the stimulus. The current stimulation also produced responses at different distances from the stimulating electrode, depending on the current magnitude.
The results show that RGC responses to a photic stimulus up to certain distances from the edge of the light spot. The electrical stimuli can mimics those distances by choosing the appropriate magnitude of current.
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