Monkeys' Recognition Memory for Complex Pictures and the Effect of Fornix Transection

Abstract

Two monkeys were trained in a running-recognition task with complex pictures. The task was made gradually more difficult by increasing the number of intervening items between the first and second presentation of the same picture. Before undergoing an operation in which the fornix was transected, both monkeys performed above 90% correct even in the most difficult task set, with up to 18 intervening items. After operation neither monkey could reliably perform a much easier task with only 2.7 intervening items on average. This impairment is comparable to that of human amnesic patients in similar tasks.