The immediate early gene Arc is required for pattern separation of non-spatial memories in the perirhinal cortex

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

Congreso; Congreso de la SAN 2016; 2015

Successful memory involves not only remembering information over time but also keepingmemories distinct and less confusable. The ability to separate the components ofmemories into distinct representations relies on pattern separation, a computationalprocess by which differences are amplified to disambiguate similar events. Despite theimportance of this mnemonic function, the molecular mechanisms necessary for thebehavioral manifestations of this process remain unknown. Although pattern separation ina spatial domain has been localized to the dentate gyrus of the hippocampus, this cognitivefunction is thought to take place also during processing of other types of information. Theperirhinal cortex (PRH) is involved in the acquisition and storage of object memories, and iscrucial for the resolution of tasks with ambiguous features. Thus, we hypothesized that thisstructure is involved in pattern separation of object memories. In this work, we used aPRH-dependent task and manipulated the load of pattern separation during encoding. Weshowed that consolidation of pattern-separated object memories depends on theexpression of the gene Arc in the PRH during a restricted time window, and that interactionbetween Arc and BDNF is necessary for successful pattern separation. These findingssuggest that Arc, an immediate early gene known to regulate synaptic plasticity andmediate memory formation, is involved in the molecular mechanisms underlying nonspatialpattern separation.