Differential role of retrosplenial cortex in object recognition memory

PEREYRA M; DE LANDETA, AB; KATCHE C; MEDINA JH

Mar del Plata

Congreso; XXXII Reunión Anual Sociedad Argentina de Investigación en Neurociencia; 2017

Several studies had demonstrated that the retrosplenial cortex (RSC) is strongly implicated on navigation and contextual memory. Furthermore, lesions in animal models show that RSC shares functional similarities with the hippocampus (Hp), suggesting that RSC has a supporting role to the hippocampal function. In this study we contrasted the role of RSC and Hp on recognition memory, particularly on the ?what? and ?where? components of this memory, using three variants of the object recognition task. Two of them focused on objects themselves (the non-spatial Y-shaped maze object recognition, Y-OR, and the spontaneous object recognition, SOR, which includes spatial cues) and the third focused on the position of the objects in the context (object location, OL). Our behavioral and molecular results demonstrate functional differences between RSC and Hp on recognition memory. When we tested the ?what? component of memory (Y-OR and SOR) the inactivation of RSC, but not Hp, impaired memory formation and expression. Moreover, there was an increase on retrosplenial, but not hippocampal, c-Fos level one hour after the animals were exposed to Y-OR sample phase. In contrast, the inactivation of both structures decreased memory index on OL task, indicating the requirement of RSC and Hp for the ?where? component of recognition memory. Our current findings suggest a novel role of the RSC in recognition memory processing, thus RSC is involved in the formation of ?what? and ?where? components of this memory.