Serial position curve in rats: role of the dorsal hippocampus.

In an eight-arm radial maze, normal rats demonstrated good immediate retention for the order of first items (primacy component of serial position curve) and last items (recency component of serial position curve) of an eight-item (arm) list. In contrast, rats with dorsal hippocampal lesions displayed, on an immediate retention test, disruption of the primacy but not the recency component of the serial position curve. Furthermore, imposing a 10-minute delay before the retention test impaired all components of the serial position curve. These results support correspondence in mnemonic function of the hippocampus in animals and humans.