Place-Field and Memory Formation in the Hippocampus

摘要

CA3 region of hippocampus may be considered as an initial storeroom for memories. During spatial memory tasks CA3 cells were found to fire in single well defined portions of a recording room (place-fields), whereas cells in both of its afferent regions, entorhinal cortex (EC) and dentate gyrus (DG), showed activity at multiple locations within an environment. DG by prior theoretical studies was proposed to be a "teacher", by dominating activity through its strong and very sparse connectivity during storage in CA3. It becomes however an intriguing question, how DG, firing at multiple locations, may set up a new spatial memory composed of exclusively single place-fields in CA3. Here we report that dentate gyrus is necessary to set up novel spatial memories in CA3 and multiple peaks of dentate gyrus may combined into mostly single fields by competitive learning in CA3.