SYSTEMWIDE REPERCUSSIONS OF DAMAGE TO THE IMMATURE VISUAL-CORTEX

Damage of the Primary visual cortex in mammals, including humans, seve rely disrupts vision by disconnecting much of the cognitive-processing machinery of extrastriate cortex from its source of visual signals in the retina. Studies of the anatomical consequences of damage to the i mmature Primary visual cortex in cats reveal system-wide repercussions on neural circuitry that includes the retina, thalamus, midbrain and extrastriate cortex. The repercussions modify circuits that support re latively normal signal processing and the sparing of certain visually guided behaviors such as aspects of complex-pattern recognition and or ienting to novel stimuli introduced into the visual field. These studi es have implications for understanding the consequences of damage to t he visual cortex in infant monkeys and humans, and for devising therap eutic strategies to attenuate defects in vision induced by cortical le sions.