Phosphene Induction and the Generation of Saccadic Eye Movements by Striate Cortex

Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts Submitted 20 July 2004; accepted in final form 7 September 2004 ABSTRACT The purpose of this review is to critically examine phosphene induction and saccadic eye movement generation by electrical microstimulation of striate cortex (area V1) in humans and monkeys. The following issues are addressed: 1 ) Properties of electrical stimulation as they pertain to the activation of V1 elements; 2 ) the induction of phosphenes in sighted and blind human subjects elicited by electrical stimulation using various stimulation parameters and electrode types; 3 ) the induction of phosphenes with electrical microstimulation of V1 in monkeys; 4 ) the generation of saccadic eye movements with electrical microstimulation of V1 in monkeys; and 5 ) the tasks involved for the development of a cortical visual prosthesis for the blind. In this review it is concluded that electrical microstimulation of area V1 in trained monkeys can be used to accelerate the development of an effective prosthetic device for the blind. Address for reprint requests and other correspondence: E. J. Tehovnik (E-mail: tehovnik{at}mit.edu )