Object-recognition memory is only mildly impaired in rats with lesions of the hippocampus and amygdala

Abstract

Rats were trained on the nonspatial delayed nonmatching-to-sample task that we recently developed to mimic the task that is commonly used to study amnesia in monkeys. The rats were tested at retention delays of 4, 15, 60, 120, and 600 sec, both before and after surgery. Each experimental rat received bilateral lesions of the hippocampus, amygdala, or both. In comparison to no-surgery control rats, the rats in each of the three experimental groups were significantly and equally impaired only at the 600-sec delay. These findings indicate that neither separate nor combined lesions of the amygdala and hippocampus cause severe object-recognition impairments in pretrained rats. © 1992, Psychonomic Society, Inc.. All rights reserved.