Consolidating unique memories: BDNF in the dentate gyrus is required for neurogenesis-dependent spatial pattern separation

PEDRO BEKINSCHTEIN

Huerta Grande

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2012

Sociedad Argentina de Investigación en Neurociencias

Successful memory involves not only remembering information overtime, but also keeping memories distinct and less confusable. Thecomputational process for making representations for similar inputpatterns more distinct from each other has been referred to as‘pattern separation’. Although adult-born immature neurons havebeen implicated in this process, information on how they wouldperform pattern separation and their particular role in memorystorage is unclear. In this work, we developed a set of behaviouralconditions that allowed us to manipulate the load for patternseparation at different stages of memory. Thus, in this work, weprovide the first experimental evidence that a BDNF-dependentpattern separation process occurs during theencoding/storage/consolidation, but not the retrieval stage ofmemory processing. We also found that a spontaneous increase inBDNF in the dentate gyrus of the hippocampus is associated withexposure to landmarks delineating similar, but not dissimilar spatiallocations, suggesting that BDNF is expressed on an “as-needed” basisfor pattern separation. Infusion of BDNF into the dentate gyrus wasable to enhance pattern separation and this effect was mediated byNMDA glutamate receptors and adult-born immature neurons,indicating a role for these cells in memory consolidation of “patternseparated” memories in the DG.