Greater residual vision in monkeys after striate cortex damage in infancy

1. Monkeys with large unilateral surgical ablations of striate cortex, sustained either in adulthood or at 5-6 wk of age, were trained on an oculomotor detection and localization task and tested with visual stimuli in the hemifields ipsilateral and contralateral to the lesion 2-5 yr after surgery. 2. Monkeys with lesions sustained in adulthood were largely unable to detect stimuli in the hemifield contralateral to the lesion, with only one monkey showing recovery toward the end of testing. Monkeys with lesions of striate cortex made in infancy, however, each showed residual detection capacity at the beginning of testing and improved to near normal by the end of testing. 3. Each of the monkeys showing a residual ability to detect within the contralateral hemifield was also able to localize visual targets with eye movements. 4. These findings demonstrate that the vision surviving striate cortex damage in primates is more robust after early damage as has been shown to be the case for primary somatosensory. motor, and association cortex.