Neuroscience Seminar: Professor Carlo A Marzi "Interhemispheric Interactions and Blindsight"

A classic discovery of about forty years ago is that some patients with hemianopia, that is, loss of vision in the half field contralateral to a unilateral lesion in the visual cortex,  display above chance  visually guided behavior in various tasks despite lack of perceptual awareness. This discovery is of great importance not only for a better understanding of how the visual system deals with an input that cannot  reach the primary visual cortex but above all for studying the neural bases of perceptual awareness . In this talk I will deal with three still open questions, namely  i) The importance  of the interactions between the intact and the blind hemisphere for giving rise to blindsight and possibly to recovery of conscious vision; ii) The question of whether blindsight is mainly subserved by the lesioned or the intact hemisphere, and finally,  iii) What kind of commissural mechanisms are involved in ensuring unconscious communication between the two hemispheres.  These questions will be discussed also in the more general  perspective of trying to understand what kind of cognitive processes are present in blindsight.