EFFECTS OF CEREBRAL LESIONS UPON OPTOKINETIC NYSTAGMUS IN MONKEYS

Abstract

Fourteen monkeys (M. mulatta) were tested for optokinetic nystagmus (OKN) before and after unilateral or bilateral lesions in the frontal, parietal, temporal and occipital lobes, alone or in different combinations. Bilateral occipital lobectomy produced a long-lasting deficit in OKN, if it also eliminated the other responses to light that were tested, except pupillary constriction and blinking. All other lesions including serial unilateral resections of 1 hemisphere failed to produce a defect in OKN. These results suggest that a minimal amount of vision, apart from pupillary and blink reactions, is necessary to obtain the optolinetic response; that homonymous loss of vision does not interfere with OKN in either direction; and that there are no special "cortical centers" for OKN in the monkey.