Further Studies of Anterior Postcentral Lesions in Monkeys

Abstract

It has recently been reported that monkeys with unilateral ablation of the hand area in the postcertral gyrus opposite the hand tested are severely impaired in somesthetic discrimination tasks. Yet earlier investigations had revealed either moderate or no impairment following complete bilateral removal of the postcentral gyri. The work reported here was an attempt to reconcile these divergent findings by exploring factors which might ameliorate the deficit: preoperative training on all tasks, a six-month recovery period, and complete or bilateral postcentral removals. None of these factors proved to be effective in lessening the severity of the impairment. It is suggested that, in the earlier studies, the representation of the finger tips near the bottom of the posterior bank of the central sulcus may have been spared.