MECHANISMS OF MEMORY LABILIZATION.

FUSTIÑANA MS; DE LA FUENTE V; FEDERMAN N; FREUDENTHAL R; ROMANO A

Munich

Congreso; 45th European Brain and Behaviour Society (EBBS) meeting; 2013

European Brain and Behaviour Society

Once a memory is consolidated, the presentation of a reminder can induce reconsolidation, involving reactivation, labilization and restabilization of the memory trace. We studied the role of the proteasome system during memory labilization in two contextual associative models, context-signal memory in the crab Chasmagnathus and fear conditioning in mouse. Our previous results show that inhibition of NF-kB during consolidation with sulfasalazine or the proteasome inhibitor MG 132, causes an amnesic effect on memory consolidation. Paradoxically, when we administered MG132 previous to the re-exposure we did not find an amnesic effect and its co-administration with sulfasalazine did not induce the expected memory impairment that normally induces the last drug. Altogether, these results support the hypothesis that the proteasome activity is necessary for memory labilization. We also studied if there is a functional role of the reconsolidation process on memory reinforcement. In both contextual associative models we re-exposed the animals several times either on the same day or in consecutive days. Memory reconsolidation was reinforced when crabs were re-exposed three times on the same day while no reinforcement was found when they were re-exposed over several days. Mice showed no reinforcement in any of the tested conditions. The implication of these results is discussed in the context of previous findings in inhibitory avoidance in rats and episodic memory in humans.