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.