Role of the lateral suprasylvian visual area in behavioral recovery from effects of visual cortex damage in cats

Abstract

The purpose of the present experiment was to determine the specific cortical areas involved in the behavioral recovery observed after visual cortex damage. Eight cats were trained preoperatively on brightness, form and pattern discriminations. They then underwent bilateral removal of visual cortical areas 17, 18, and 19. Postoperatively, the cats showed a loss of the learned discriminations. In agreement with previous studies, they were able to recover their visual discrimination ability, and all 8 cats reattained criterion performance on all three discriminations. Retention tests of the postoperatively learned tasks were then conducted after a period of 40 days or more. They showed that cats with visual cortex lesions have good retention of easier discriminations, but show some forgetting of more difficult tasks. Following the visual cortex lesion and recovery, 4 cats received a second lesion of the crown of the middle and posterior suprasylvian gyri (CROWN group). This produced no loss of the discriminations beyond what is expected on the basis of forgetting, as determined by the retention tests. The remaining cats received a second lesion which included the lateral suprasylvian visual area in the middle and posterior suprasylvian sulci (LS group). In two of these animals, the lesion also damaged some of the crown of the suprasylvian gyrus (LS + CROWN group). These lesions produced a second loss of the form and pattern discriminations, and relearning was more prolonged than that following damage to visual cortex alone. There was no difference between the LS and the LS + CROWN groups. These results indicate that the lateral suprasylvian visual area plays an important role in the behavioral recovery of form and pattern discrimination ability following visual cortex damage in cats.