Estimating Phosphene Maps for Psychophysical Experiments used in Testing a Cortical Visual Prosthesis Device

Visual prosthesis devices are being developed to restore vision for those with blindness. Researchers working in the field of visual prosthesis are taking different approaches to develop a practical device. Some are targeting the retina for stimulation, whereas at least one group is targeting the optical nerve, and our laboratory is developing a system for the visual cortex. To estimate the kind of response they might expect from a typical user, researchers are conducting psychophysical experiments on normally-sighted persons. The device being developed in our laboratory is a first generation visual prosthesis system, designed to test the limits of artificial visual pattern recognition. Targeting the visual cortex area with our first generation device has limitations including limitations in lateral cortical surface area for electrode implantation, surgical difficulties and the lack of understanding as to how to use an artificial interface for communication with the visual cortex. Here, we discuss the uncertainties related to visotopic mapping of the lateral surface of the occipital lobe in humans.