Long-term memory formation of object in context task requires medial prefrontal cortex activity and it is interfered by another object in context experience

VILLAR ME; MARTINEZ MC; BALLARINI F; VIOLA H

Cordoba

Congreso; Sociedad Argentina de Neurociencias; 2013

Recognition memory refers to the ability to identify an object or a situation and judge if it was previously experienced or not. In particular, the recognition of an item in connection with a context (what-where) constitutes an important element of episodic memory, which  also implies remembering about what-when. Here, we reveal that the acquisition of information about object-context association put in risk the long-term memory (LTM) expression for a previously learned associate object-context pair.  Also, we investigated the effective temporal window of that interference, the required features of the interpolated material to be effective, as well as the brain regions involved in the phenomenon. Our results show that LTM formation for a novel object associated with a context (but not the object recognition LTM) can be impaired if rats are subsequently exposure to a different object in context experience. Thus, the second learning experience can exert retrograde interference over the first one, in a limited temporal window. Finally, our results strongly suggest that the medial prefrontal cortex and dorsal hippocampus are important brain regions involved in the processing of both pairs of association and when both of them are being consolidated at overlapping time course, a competition occurs and only one of them could be store.