HIPPOCAMPUS AND RESPONSE PERSEVERATION IN CAT

This series of experiments has shown that cats with hippocampal ablations are more resistant to extinction of a food rewarded instrumental response, and that no between group differences were found in the re-acquisition of this same instrumental response. The lesioned subjects were superior to the control subjects in learning a non-spatial delayed alternation. There were no differences on spatial alternation, but the lesioned animals were significantly impaired on a series of daily spatial reversals. The results of these experiments are discussed with reference to the response perseveration, motivation, memory, and orienting response hypotheses of hippocampal functioning. It was concluded that the present findings are not amenable to a unitary interpretation of the functional role of the hippocampus. More-over, it is speculated that some additional system concerned with the experience of reward may be released from hippocampal influences as a result of the lesion. Such a speculation would help to explain the superior performance of the lesioned animals on the test of non-spatial alternation. © 1969.