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

Córdoba

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2018

Sociedad Argentina de Investigación en Neurociencias

The recall of a consolidated memory by the presentation of the conditioned stimulus induces a labile state followed by a process of stabilization dependent on protein synthesis referred as memory reconsolidation (Nader et al 2000, Dudai 2006).In this way, the process of labilization-reconsolidation presents a temporal course that is vulnerable to interfering agents. However, a negative emotional state, generated by a stressful event, limits the occurrence of such process and induces a resistance of the memory trace to the amnesic effect of the interfering agents (Bustos et al. 2010, Ortiz et al. 2015). The Basolateral Amygdala Complex (BLA) plays a key role on emotional information processing as well as on the formation and recall of a contextual fear memory. In the same way, experimental evidences grant the dorsal Hippocampus (DH) the contextual representation of such fear memory through functional interconnections between both areas. The majority of the excitatory contacts between neurons reside on dendritic spines (Yuste and Denk 1995). Different experimental evidences have shown that the substrate for the storage of long-term memories, including contextual fear memories underlie on an appropriate structural plasticity in the form of changes in spine density, in critical brain regions following learning (Kandel 2001; Restivo et al 2009). In the present work we evaluated whether fear memory reactivation impacts on the dendritic spines remodeling in CA1 region of the dorsal hippocampus associated with the formation of the contextual fear memory. In the same way, we asked whether stress exposure affects such dendritic spine remodeling.