Interhemispheric cuing systems remaining after section of neocortical commissures in monkeys

Abstract

Split-brain monkeys permanently fitted with goggles equipped with a red filter over one eye and a blue filter over the other were placed in a specially-designed testing apparatus which could be illuminated by either red or blue light. They were trained and maintained in blue light, thereby allowing vision through only the eye covered with the blue filter. Under these conditions other visual stimuli were briefly presented to the opposite hemisphere in red light. Stimuli with emotional quality presented in this manner were distractive and could affect the normal performance of the ongoing activity of the opposite working hemisphere. Additionally, if a fear-producing stimulus was directly presented to a hemisphere while it was engaged in some visuomotor task, immediate testing of the opposite hemisphere showed it to be relatively undisturbed provided the exposure was brief. With protracted exposure, the animal's behavior was found to be equally disturbed in each hemisphere.