Effects of combined frontal and temporal lesions on learned behaviors in rhesus monkeys.

Delayed response ability, and to a lesser extent visual discrimination performance, is seriously impaired by extensive bilateral damage to the frontal lobes. Reciprocal anatomical connections between the frontal and temporal lobes suggested that massive lesions in both lobes might produce an impairment more complete than that resulting from frontal lobectomy alone. Five monkeys were given combined bilateral frontal and anterior-temporal lesions, and were found to be inferior to both frontal lobectomized monkeys and to unoperated controls on the object discrimination task. The combined lesion did not increase the deficit on delayed response over that obtained after only bilateral frontal lobectomy. Results indicate that the anterior-temporal neocortex is involved in the mediation of visual discrimination ability.