The proposed research will use selective lesion techniques to assess the role of the hippocampal formation in learning and memory in rhesus monkeys. Specifically- the effects of ibotenic acid induced damage to the hippocampal formation will be compared with those of aspiration lesions of rhinal cortex and transections of the fornix on five behavioral tasks: 1) list learning, as measured by the serial probe recognition task; 2) relational learning, as measured by the transverse patterning problem; 3) spatial learning, as measured by an analog of the radial arm maze; 4) recognition memory, as measured by performance on trial-unique delayed nonmatching-to- sample; 5) concurrent discrimination learning, as measured by the 24 hour intertrial interval task. These experiments are designed to discover what role, if any, the hippocampal formation (or its interaction with cortical and subcortical structures) has to play in the above memory systems.
