SELECTIVE DAMAGE TO THE HIPPOCAMPAL REGION BLOCKS LONG-TERM RETENTIONOF A NATURAL AND NONSPATIAL STIMULUS-STIMULUS ASSOCIATION

Normal rats rapidly acquire and remember associations between nonspati al stimuli as expressed in the social transmission of food preferences . In the present study, rats with selective neurotoxic lesions includi ng all subdivisions of the hippocampal region (hippocampus proper, den tate gyrus, and subiculum) normally acquired and briefly retained the food odor association as demonstrated by intact memory immediately aft er social training. However, long-term memory in these animals was sev erely impaired in contrast to strong 24-h retention by intact rats. Mo re selective lesions to the hippocampus proper plus dentate gyrus alon e, or the subiculum alone had no effect on memory at either test inter val. These findings indicate that the hippocampal region is required f or long-term retention of a nonspatial form of natural memory. (C) 199 5 Wiley-Liss, Inc.