LEARNING AND RECALL OF FORM DISCRIMINATIONS DURING REVERSIBLE COOLINGDEACTIVATION OF VENTRAL-POSTERIOR SUPRASYLVIAN CORTEX IN THE CAT

Extrastriate visual cortex of the ventral-posterior suprasylvian gyrus (vPS cortex) of freely behaving cats was reversibly deactivated with cooling to determine its role in performance on a battery of simple or masked two-dimensional pattern discriminations, and three-dimensional object discriminations. Deactivation of vPS cortex by cooling profoun dly impaired the ability of the cats to recall the difference between all previously learned pattern and object discriminations. However, th e cats' ability to learn or relearn pattern and object discriminations while vPS was deactivated depended upon the nature of the pattern or object and the cats' prior level of exposure to them, During cooling o f vPS cortex, the cats could neither learn the novel object discrimina tions nor relearn a highly familiar masked or partially occluded patte rn discrimination, although they could relearn both the highly familia r object and simple pattern discriminations. These cooling-induced def icits resemble those induced by cooling of the topologically equivalen t inferotemporal cortex of monkeys and provides evidence that the equi valent regions contribute to visual processing in similar ways.