Effects of context manipulation on memory and reversal learning in rats with hippocampal lesions.

Abstract

Groups of hippocampal and control rats learned a simultaneous discrimination habit and were subsequently tested for its retention under variable contextual conditions. All groups recalled the discrimination response to an equally high level when testing conditions were constant throughout, but the hippocampal group showed impaired memory when contextual stimuli at recall testing did not conform to those of original learning. The hippocampal impairment was not simply the result of introducing novel stimuli. Animals were administered a reversal learning task with contextual stimuli varied between the 2 tests. The typically observed impairment of hippocampal animals on this task was reduced by contrasting contextual conditions. The data support a context-retrieval interpretation of hippocampal function.