Role of Medial Prefrontal Cortex and Perirrhinal Cortex during Reconsolidation in Object Recognition Memory in Rats

MORICI FACUNDO; GALLO FRANCISCO; MIRANDA MAGDALENA; BEKINSCHTEIN, PEDRO; NOELIA WEISSTAUB

huerta grande

Congreso; XXVIII Congreso Anual de la Sociedad Argentina de Investigaciones en neurocienicas; 2014

Sociedad Argentina de Investigaciones en Neurociencias

Episodic memory contains information regarding ?what?, ?where? and ?when?. In rodents, is evaluated using the spontaneous object recognition task (SOR). The perirhinal cortex (PRH) plays a critical role in object recognition, however other structures are also involved. We have shown that serotoninergic modulation of medial Prefrontal Cortex (mPFC) is involved during retrieval in versions of the SOR in which the memory of the object is associated with temporal or spatial information, like the object in context task (OIC). We suggest that mPFC exerts top-down inhibition of the less relevant information. During reconsolidation, consolidated memories become labile again after reactivation. We propose that reconsolidation in the OIC will occur only for the reactivated (retrieved) object memory trace. However, it is still unknown if reconsolidation occurs in this task; and which structures are involved. The goal of this work was to determine if there is reconsolidation in the OIC  and the role of mPFC and PRH cortices in it. Infusion of emetine in the PRH after the retrieval blocked the reconsolidation of only one of the object memories. However, infusion of 5-HT2a antagonist in mPFC allowed labilization of both memory traces during the retrieval making them susceptible to emetine. These results suggest that there is reconsolidation in the OIC and that 5-HT2a receptors in mPFC control memory reactivation allowing the expression and reconsolidation of the most relevant memory trace.