The perirhinal cortex and long-term spatial memory in rats.

Two experiments examined the effects of perirhinal cortex and hippocampal neurotoxic lesions on the retention of allocentric information. Perirhinal (Expt. 1) and hippocampal rats (Expt. 2) were trained on an allocentric task until they reached a performance equal to that of the control groups. Results showed that 24 days after acquisition, during a retraining period, only the hippocampal rats presented a deficit in retention. These results suggest that the perirhinal cortex and the hippocampus can be functionally dissociated in terms of their participation in the formation of long-term spatial memory. Also, the allocentric spatial memory functions of the hippocampus seem not to depend on their afferent connections with the perirhinal cortex.