Humans and non-human primates both retain a limited amount of residual vision in their blind field after primary visual cortex (striate or V1) damage, but the anatomical substrates of these abilities are not currently well understood. The proposed project will test the hypothesis that the hemisphere contralateral to a unilateral striate lesion contributes to the residual visual abilities seen in the blind field. This project will seek for evidence to support one of the following three possibilities: (1) The intact hemisphere contributes to residual vision by expanding the naso-temporal overlap at the vertical meridian only. (2) The intact hemisphere contributes to residual vision by reorganizing its cortical topography at both the vertical meridian representation and in other parts of the visual field. (3) The intact hemisphere does not contribute to residual vision in the blind field. Each of these possibilities will be tested in a monkey model of residual vision with visual evoked potentials (VEPs), single-unit recordings, and the anatomical tracing of connections to and from the intact contralateral striate cortex. The results of this study could be used to help understand and restore lost vision in humans.
