Rabbit Retinal Ganglion Cell Activation Thresholds in Response to Various Electrical Stimulation Waveforms using a Different Spatial Resolution Electrode Array

Abstract

The analysis of retinal ganglion cell responses to electrical stimulation is invaluable way to understand how the retina reacts and develops. Artificial visual prosthetics have made progress to some extent. Although there are several studies about retinal ganglion cell responses in the literature, experimental findings and information about responses to special stimulation patterns for developing high-resolution visual prosthetics are quite limited. In this study, rabbit retinal tissue was stimulated by biphasic, monophasic and ramp function current pulses with various amplitudes and pulse widths in a set of in vitro experiments. Rabbit retinal ganglion cell responses and spike activities are comparatively analyzed based on the applied electrical stimulation parameters. We conclude that biphasic current pulses provide a lower stimulation threshold of 10 mu A with shorter pulse widths than those obtained by monophasic stimulation. Additionally, despite the fact that ramp function stimulation patterns have remarkable potential for eliciting spike formation with low stimulation thresholds, biphasic stimulation is charge-balanced and more convenient for high-resolution visual prosthesis systems.