Abstract

This study was an attempt to examine dorsal hippocampal lesion effects on learning and retention in two way active avoidance task. Especially, the effects of contextual changes on retention in rats with dorsal hippocampal lesions were evaluated. Hippocampal and control rats learned two way active avoidance task and were subsequently tested for its retention under the same or different contextual conditions. Animals with hippocampal 1 的ions clearly reached our learning criterion more rapidly than the controls. Both groups showed equally good savings of the avoidance learning in the same contextual conditioning, but the hippocampal group showed impaired memory when contextual cues at retention testing did not conform to those of original learning. The data are seen to support a context hypothesis.