The hippocampus has been suggested to support multiple memory processes including pattern separation, working memory, and the formation of arbitrary associations. Therefore, the first aim of the proposed grant will be to develop behavioral paradigms to assess pattern separation, working memory, and the formation of arbitrary associations in rats. Based on computational models and behavioral data, a model of hippocampal function has been proposed in the present grant which localizes particular processes to particular hippocampal subregions. Therefore, the second aim of the proposed grant will be to test the hypothesis that the mechanisms which support processes such as pattern separation, working memory, and the formation of arbitrary associations can be localized to a particular subregions of the hippocampus. Finally, computational models suggest that the hippocampus and its subregions support these processes for spatial and nonspatial information. However, the proposed model suggests that the hippocampus only supports these processes for spatial and temporal information. Therefore, the third aim of this grant will be to test the hypothesis that the subregions of the hippocampus support pattern separation and the formation of arbitrary associations only for spatial and temporal information but not nonspatial and nontemporal information.