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

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

Huerta Grande

Congreso; XXIX Congreso de la Sociedad Argentina de Neurociencias.; 2014

Sociedad Argentina de investigación en Neurociencias

Episodic memory, corresponds to the type of memories that contain information regarding ?what?, ?where? and ?when?. In rodents, different aspects of episodic memory can be evaluated using particular versions of the spontaneous object recognition (SOR) task. The perirhinal cortex (PRH) plays a critical role in object recognition, however other structures have also been involved  We have previously shown that serotoninergic modulation of medial Prefrontal Cortex (mPFC) is involved the control of object memory retrieval in some versions of the SOR task in which the memory of the object is associated with temporal or spatial information, like the object in context (OIC) task, We suggest that in order to reduce interference, mPFC exerts top-down inhibition of the less relevant information, like one of the object memory traces. Reconsolidation is the process by which consolidated memories become labile again after reactivation. We propose that reconsolidation in the OIC task will occur only for the reactivated (retrieved) object memory trace. However, it is still unknown if reconsolidation process even occurs in this task; and which structures are involved. The goal of the present work was to determine if there is reconsolidation in the OIC task and the possible role of the mPFC and PRH cortices during this process. Using male Wistar rats we have found that infusión of emetine in the PRH cortex immediately after the retrieval blocked the reconsolidation of only one of the object memories in the OIC task. However, infusion of 5-HT2a antagonist in the mPFC allowed labilization of both object memory traces during the reactivation phase making both of them susceptible to emetine..These results suggest that there is reconsolidation in the OIC task and that 5-HT2a receptors in mPFC control memory reactivation allowing the expression and reconsolidation of the most relevant memory trace.