The anatomy of memory: circuitry and functions of the hippocampal-parahippocampal region.

The human hippocampal-parahippocampal region plays an important role in memory. The relationship between the circuitry contained in this brain region and its contribution to memory is a topic of intense research, yet to date there is no complete and mecha nistic understanding of how the circuitry underpins memory. The research outlined in this project proposal will exactly address this; integrating structural studies of hippocampal-parahippocampal circuits with a study on their roles in memory; three studi es are envisioned. The first study will result in a detailed comparison of the parahippocampal-hippocampal circuitry between humans, monkeys and rats. This comparison provides an essential link for the interpretation of research carried out in rodents and monkeys and their relevance for humans. The second study will result in a methodological advancement; A Manganese Enhanced Magnetic Resonance Imaging (MEMRI) protocol will be developed which can be used to study projections within the rat hippocampal-par ahippocampal region in vivo at a truly microscopic level, such that it can be used to determine differences in projection targets within a single cortical layer. The third study will advance knowledge of the neural activity that occurs in the human hippoc ampal-parahippocampal region during the creation and usage of knowledge structures called schemas, which are known to enhance the formation of memory.