Same context, different objects, long-term memory failure in object recognition.

VILLAR ME; MARCHAL P; MARTINEZ MC; BALLARINI F; LOPES DA CUNHA, P; VIOLA H

Montevideo

Congreso; International Congress of Neuroethology, Uruguay, Montevideo, 30 March - 3 April 2016.; 2016

With the aim of analyzing if object recognition long-term memory(OR-LTM) formation is susceptible to retrograde interference (RI), we submitted rats to sequential familiarizationsessions using the same arena but changing the identity of the objects. Separate groups of subjects weretested in the arena in order to evaluate the LTM for both objects. We investigatethe existence of a RI process, if it could operate within theconsolidation window, what kind of events is able to interfere with OR-LTM. Furthermore, given the involvementof hippocampus (Hp) and medial prefrontal cortex (mPFC) in several recognitionmemories, we analyzed the participation of these structures in OR-LTM formationby using local infusion of muscimol.Our results suggest that OR-LTMformation was retrograde interfered by a new (but not familiar)object explored in the same arena, within a critical time window. This RI actedon the consolidation process, because in the test session performed three hourafter familiarization, STM expression was not affected but LTM measured 24hafter familiarization was impaired. Moreover, local inactivation of the dorsalHp or mPFC previous to the exploration to the second object pair impaired itsconsolidation restoring the LTM for the objects explored in thefirst session. These data suggest that both brain regions are involved in processingOR task and that if they were engaged in another process before finishing theconsolidation of the former process, its LTM will be impaired by RI.