Topographic restoration of visual spatial attention in the cortically blind cat

Abstract

We explored the mechanisms of spatial attention in the cat with a combination of permanent and reversible lesion techniques. Animals with large unilateral visual cortical lesions displayed profound blindness of contralesional visual space. However, cooling deactivation of either posterior parietal cortex or the superior colliculus (SC) in the contralesional half of the brain restored visual orienting responses in the blind hemifield. Interestingly, gradual SC deactivation by decreasing cooling loop temperatures produced a topographic restoration of orienting responses, starting at the midline and progressing towards more peripheral eccentricities in the previously blind field. These effects can be explained within a computational model for spatial orienting, which represents the interhemispheric competition of bilateral brain structures that possess a topographic, center-magnified representation of the external visual space. © 2002 Published by Elsevier Science B.V.