Layers IV and V Pyramidal Neurons of A29 Are Required for Disambiguate Emotionally Relevant Contexts

ERIC L. SIGWALD; DE OLMOS S; ALFREDO LORENZO

Córdoba

Congreso; XXXIII Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2018

Sociedad Argentina de Investigación en Neurociencias

Retrosplenial cortex (RSC) is divided in two anatomicallydistinct subregions: A29 and A30, but the functional role ofeach subunit in cognitive processing remains elusive. Systemicapplication of MK801 causes elimination of pyramidal neurons in layers IV and Va of A29 (A29MK801 neurons), without affecting A30 or other brain areas. Previously, we showedthat selective loss of A29MK801 neurons did not affect freezing behavior but significantly impairs A30-activation and theretrieval of contextual fear memory (CFM). To dissect thefunctional role of A29MK801 neurons in CFM first we usedopen field and elevated plus maze tests and found that loss ofA29MK801 neurons have no anxiolytic effect, suggestingthese neurons are not required for risk assessment duringCFM. Elimination of A29MK801 neurons did not impair contextual recognition as assessed by object in place tests or byan A-B-A design of contextual fear test. However, eliminationof A29MK801 neurons completely abolishes retrieval of fearmemory associated to preconditioned stimuli in higher-orderconditioning. However, in a higher-order conditioning paradigm elimination of A29MK801neurons completely abolishesretrieval of fear memory associated to preconditioned stimuli. Altogether, our data suggest that A29MK801 neurons arecritically required for the retrieval of complex contextualassociation memories with emotional relevance likely byimpairing the activation of A30.