Molecular Mechanisms in Perirhinal Cortex Selectively Necessary for Discrimination of Overlapping Memories, but Independent of Memory Persistence. Miranda M, Kent BA, Morici JF, Gallo F, Weisstaub NV, Saksida LM, Bussey TJ, Bekinschtein B. 2017

AUTORES Miranda M, Kent BA, Morici JF, Gallo F, Weisstaub NV, Saksida LM, Bussey TJ, Bekinschtein B.
AÑO 2017
JOURNAL eNeuro
VOLUMEN October, 2017
ABSTRACT Successful memory involves not only remembering over time but also keeping memories distinct. The ability to separate similar experiences into distinct memories is a main feature of episodic memory. Discrimination of overlapping representations has been investigated in the dentate gyrus of the hippocampus (DG), but little is known about this process in other regions such as the perirhinal cortex (Prh). We found in male rats that perirhinal brain-derived neurotrophic factor (BDNF) is required for separable storage of overlapping, but not distinct, object representations, which is identical to its role in the DG for spatial representations. Also, activity-regulated cytoskeletal-associated protein (Arc) is required for disambiguation of object memories, as measured by infusion of antisense oligonucleotides. This is the first time Arc has been implicated in the discrimination of objects with overlapping features. Although molecular mechanisms for object memory have been shown previously in Prh, these have been dependent on delay, suggesting a role specifically in memory duration. BDNF and Arc involvement were independent of delay-the same demand for memory persistence was present in all conditions-but only when discrimination of similar objects was required were these mechanisms recruited and necessary. Finally, we show that BDNF and Arc participate in the same pathway during consolidation of overlapping object memories. We provide novel evidence regarding the proteins involved in disambiguation of object memories outside the DG and suggest that, despite the anatomical differences, similar mechanisms underlie this process in the DG and Prh that are engaged depending on the similarity of the stimuli.
RESUMEN Muchas veces se asocia la pérdida de memoria con la imposibilidad de recordar items luego de un intervalo de tiempo. No obstante, la amnesia puede ocurrir porque dos experiencias o ítems fueron similares y al momento de recordarlos, se confunden. El cerebro posee mecanismos para transformar la información proveniente de experiencias similares en memorias diferenciadas que sean menos confundibles al momento de evocarlas. En este trabajo demostramos que los mecanismos moleculares involucrados en el almacenamiento de experiencias similares como memorias diferentes son similares en el dominio espacial y en el de objetos. Estos mecanismos involucran la acción del factor neurotrófico derivado de cerebro (BDNF) tanto en el hipocampo como en la corteza perirrinal, necesarios para el almacenamiento de información espacial y de objetos respectivamente. A pesar de ser dos estructuras anatómicamente muy diferentes, los mecanismos moleculares necesarios para el procesamiento de este tipo de memorias es similar.