V-040 | Lateral Entorhinal Cortex as a Bridge Between Amygdala and Hippocampus in the destabilization/reconsolidation of Contextual Fear Memories

Cognition, Behavior, and Memory
Author: Ramiro Gabriel Comas Mutis | Email: ramiro.comas@unc.edu.ar

Ramiro Gabriel Comas Mutis^1°2°, Melisa Riva Gargiulo^1°2°,Gastón Diego Calfa^1°2°

^1° IFEC – CONICET.
^2° Departamento de Farmacología Otto Orsingher, FCQ, UNC.

The destabilization/reconsolidation of fear memories has been regarded as a potential therapeutic target for the treatment of disorders such as phobias and Post Traumatic Stress Disorder (PTSD). In this sense, it has been shown that the interaction between the basolateral amygdala (BLA) and the Dorsal Hippocampus (DH) is critical for this process to occur, even though there are no direct connections between them. However, acute stress exposure prior to the acquisition generates robust memories resistant to destabilization, from a synaptic standpoint, rendering them impervious to interference. Moreover, stress affects the temporal dynamic of the DH structural plasticity associated with the destabilization/reconsolidation process and the interaction between BLA and DH, generating dichotomic effects in both structures.
We set to investigate how BLA and DH connect during the destabilization/reconsolidation process and how stress affects this circuit. Here we provide evidence that the Lateral Entorhinal Cortex (LEC) works as a functional mediator in the emotional pathway of memories, modulating the influence of BLA on DH. Through electrophysiological recordings in layers V and II of LEC we proved that memory destabilization is accompanied by a decrease in excitatory activity of principal cells that does not occur in stressed animals which, in turn, affects the information that enters DH.