Spatial novelty interferes with long-term memory persistence during a late critical time window

DORMAN, GUIDO Y KATCHE, CYNTHIA; GOLDIN, ANDREA; SLIPCZUK, LEANDRO; MEDINA, JORGE H.

Huerta Grande, Córdoba

Congreso; I Reunión Conjunta de Neurociencias (IRCN). XI Taller Argentino de Neurociencias. XVII Reunión de la Sociedad Argentina de Investigación en Neurociencias (SAN); 2009

Persistence is a characteristic attribute of long-term memories (LTMs). We recentlyshowed that persistence of LTM requires a late protein synthesis-dependent phase in thehippocampus. Nevertheless, little is known about the effect of the acquisition of newinformation on LTM persistence. Here, we demonstrate that exposure to a novelenvironment (an open field, OF) 11h after an strong inhibitory avoidance training (IA)interferes with the persistence of this memory trace 7 days, but not 2 days after training.This effect is observed during a critical time window since exposure to a novel OF 5hand 8h post training does not affect IA memory. However, the interference is absentwhen the OF is familiar. In addition, when OF memory formation is blocked by intrahippocampusinfusion of KN62 –a CamKII inhibitor-, the effect of the exploration ofthe novel OF on LTM persistence of IA training is completely prevented. Based onthese results, we suggest that IA LTM persistence can be interfered by exposure to anovel, but not a familiar environment 11hs after training. A possible explanation couldbe that these two memories compete for proteins products thus decreasing theavailability of proteins necessary for LTM persistence of IA memory.