Temporal dynamic of the hippocampal structural plasticity associated to contextual fear memory: influence of the destabilization/reconsolidation process

Cordoba

Congreso; XXXIII Congreso anual de la Sociedad Argentina de Investigación en Neurociencias; 2018

Sociedad Argentina de Investigación en Neurociencias

Increasing experimental evidences indicate that a mnesic trace reactivation induces a transient plastic state that reactivates the neuronal circuit encoding the internal representation of the fear memory. Under this circumstance, it is allow incorporating and integrating new information to the original one. Here, we evaluated whether the reactivation of a fear memory impact on the dendritic spines remodeling in CA1 dorsal hipocampus associated with contextual fear memory. In the same way, we asked whether stress exposure affects such dendritic spine remodeling. Thus, stressed and control animals were fear conditioned and 24hs post conditioning, 60min post retrieval or 24hs post retrieval animals were sacrificed.A higher expression of dendritic spines, particularly mature ones, observed after fear encoding was reduced to basal levels 60min after fear reactivation returning to the prior higher levels 24hs post retrieval. This temporal dynamic structural plasticity was prevented by blocking in basolateral amigdala complex the destabilization/reconsolidation process or even a single stress exposure just before conditioning. Thus, the destabilization/reconsolidation process was evidenced by a change in the hippocampal structural plasticity immediately following reactivation, a plausible necessary step for the integration of new information.