CRITICAL ROLE OF THE PARAHIPPOCAMPAL REGION FOR PAIRED-ASSOCIATE LEARNING IN RATS

Human amnesics are severely impaired in learning arbitrary association s between word pairs. This report examines the role of the hippocampal system in an analog of paired-associate learning developed for rats. Subjects with selective damage to the parahippocampal region and contr ols were tested on an odor-guided paired-associate task. Normal rats r eadily learned to distinguish paired associates from various mispairin gs of the same odors, whereas most animals with parahippocampal damage failed to learn. Lesioned animals were, however, able to acquire corr ect responses to stimulus pairs for which an association between odors was not required. These findings extend the usefulness of olfactory l earning as a model for studies of higher order learning capacity in ro dents and indicate that in rats, as in humans, hippocampal areas are c ritical for learning arbitrary nonspatial relationships between stimul i.