Role of the 5-HT2a receptors in the resolution of memory interferences during retrieval”

PEDRO BEKINSCHTEIN; MARIA RENNER; NOELIA V WEISSTAUB

New Orleans

Congreso; 42nd Annual Meeting of the American Society for Neuroscience. New Orleans USA.; 2012

Society for Neuroscience

The medial Pre Frontal Cortex (mPFC) has been involved in complex integration of information necessary during response selection and interference. The interference theory refers to the idea that forgetting occurs because the recall of certain items interferes with that of other items. Thus, the retrieval of two memory traces that share certain neuronal circuits will activate the PFC to prevent interference resulting in the forgetting or suppression of one of the traces in favor of the other one. The mPFC is modulated by many neurotransmitter systems including the serotonergic system. Serotonin (5-HT) acts through 14 different receptors. In the mPFC one of the most important one is the 5-HT2a receptor. It is not clear which is the role of the serotonergic system in memory interference processes. In this work we evaluate the role of mPFC 5-HT2a receptors in memory interference using different versions of the object recognition task in rats. We found that infusion of 5-HT2a antagonist in the mPFC 15 minutes before retrieval alter the response in the temporal order and object in context tasks but not in the spontaneous object recognition task. Blockage of 5-HT2a, but not 5-HT2C receptors affects the ability of mPFC to avoid memory interference. Activation of 5-HT1a receptors also produces behavioral deficits. Immunohistochemical analysis indicates that memory interference correlates with increase expression of immediate early genes expression in the perirhinal cortex, suggesting that mPFC activity modulate the activity of other regions involved in object recognition.