Possible blindsight in infants lacking one cerebral hemisphere

Abstract

PATIENTS with damage to the striate cortex have a subjectively blind region of the visual field, but may still be able to detect and localize targets within this region1,2. But the relative roles in this 'blindsight' of subcortical neural systems, and of pathways to extra-striate visual areas, have been uncertain3. Here we report results on two infants in whom one cerebral hemisphere, including both striate and extra-striate visual cortex, needed surgical removal in their first year. Single conspicuous targets in the half-field contralateral to the lesion could elicit fixations, implying detection and orienting by a subcortical system. In contrast, binocular optokinetic nystagmus (OKN), for ..