Hippocampal Neurogenesis-mediated Forgetting in Adult Mice

New neurons are continuously generated in the dentate gyrus of the hippocampus throughout adulthood. These new neurons gradually integrate into hippocampal circuitry, which likely support the formation of new memories. Once sufficiently mature, however, as they integrate into existing circuits, they may also disrupt pre-existing memories stored in those circuits. Recently, we found artificially elevating levels of adult neurogenesis through voluntary running exercise or p53 ablation after memory formation promoted degradation in contextual fear memories and spatial memories. Besides, Mice with elevated neurogenesis levels immediately after training or after a 4 weeks delay had different freezing responses to a fearful context. Only increasing levels of neurogenesis immediately but not after a long delay after training induced forgetting, suggesting that as memories age, they become less vulnerable to neurogenesis-mediated forgetting possibly due to a reduced involvement of the hippocampus in the retrieval of memories over time.%%%%M.Sc.%%%%2017-11-25 00:00:00