Thalamic Visual Prosthesis Project

Abstract

The lateral geniculate nucleus of the thalamus (LGN) is a well-studied structure in the early visual pathway that links the retina to the primary visual cortex. As a deep structure, it has been long overlooked by the visual prosthesis field due to surgical inaccessibility. The unrelated field of deep brain stimulation has developed safe and effective means for clinical implantation of stimulating electrodes in structures that are near the LGN, removing the primary barrier for consideration of the thalamus as a stimulation target for artificial vision. In this chapter we review current progress toward creation of a thalamic visual prosthesis, describing initial animal experiments as proof-of-concept with single microwire electrodes, computer simulations of electrode placement and the resulting pattern of phosphenes in the visual field, experiments with sighted human volunteers to assess effective acuity of artificial vision using virtual reality simulations, and finally results from training animals in an artificial vision simulation in preparation for implantation of stimulating electrodes.