Abstract
Visual prostheses aim to restore vision to people blinded from degenerative photoreceptor diseases by electrically stimulating surviving neurons in the retina. However, a major challenge with epiretinal prostheses is that they may accidentally activate passing axon fibers, causing severe perceptual distortions. To investigate the effect of axonal stimulation on the retinal response, we developed a computational model of a small population of morphologically and biophysically detailed retinal ganglion cells, and simulated their response to epiretinal electrical stimulation. We found that activation thresholds of ganglion cell somas and axons varied systematically with both stimulus pulse duration and electrode-retina distance. These findings have important implications for the improvement of stimulus encoding methods for epiretinal prostheses.
Footnotes
Supported by the Washington Research Foundation Funds for Innovation in Neuroengineering and Data-Intensive Discovery, by a grant from the Gordon and Betty Moore Foundation and the Alfred P. Sloan Foundation to the University of Washington eScience Institute Data Science Environment, and by the National Institutes of Health (NIH K99 EY-029329). The Titan Xp graphics card was donated by the NVIDIA Corporation. The author would like to thank Fred Rieke and Geoffrey M. Boynton for helpful discussions on the modeling of retinal ganglion cells as well as Ariel Rokem and Ione Fine for feedback on the manuscript.
