Blindsight: The role of feedforward and feedback corticocortical connections

Discusses the phenomenology and neural substrate of blindsight and the dissociation between visual awareness and other types of visually guided behavior. Ss with blindsight, in which a lesion to the primary visual cortex results in loss of visual percepts in the region of space that corresponds to the site of the lesion, are still capable of responding to stimuli in the region when asked to guess or execute related forced-choice motor commands. The possible roles of feedforward and feedback corticocortical connections in the visual brain in the elucidation of blindsight are reviewed. What emerges is described as substantial evidence in favor of the theory that unconscious visuo-motor transformations, as in blindsight, may be executed in an entirely feedforward processing cycle, while visual awareness is critically dependent on feedback connections to the primary visual cortex.