INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Differential activation of the subdivisions of retrosplenial cortex associated to the retrieval of fear conditioned memory.
Autor/es:
NICOLAS PONCE; SOLEDAD DE OLMOS; ERIC L SIGWALD; VICTOR A. MOLINA; ANAHI BIGNANTE; ALFREDO LORENZO
Lugar:
Puerto Varas
Reunión:
Congreso; XXX Reunión Anual de la Sociedad de Biología Celular de Chile.; 2016
Institución organizadora:
Sociedad de Biología Celular de Chile
Resumen:
The retrosplenial cortex (RSC) has been implicated in complex cognitive functions such as learning, memory, spatial navigation and introspection. Consistent with these functions, connections of the RSC include the anterior and lateral nuclei of the thalamus, the visual, entorhinal, prefrontal and prelimbic cortices and the hippocampal formation (Vann et al., 2009). The RSC is subdivided in two main regions, A29 and A30, according to their cytoarchitectural organization and connections. However, little is known about the functional activity of each RSC subdivision and neuronal subpopulations during the execution of complex cognitive tasks. Similar to other cortical areas, the neuronal composition of the RSC includes two main types of neurons: projecting glutamatergic neurons and interneurons, the latter subdivided in the stellate glutamatergic neurons located in layer IV, and the smooth nonpyramidal GABAergic neurons, located in all layers except layer I (DeFelipe, 1997). Dysfunction of RSC is associated with diverse pathological conditions such as Alzheimer´s disease, autism or schizophrenia (reviewed by Vann et al. 2009; Vogt et al. 2004). Therefore, elucidating the anatomofunctional organization of the RSC might shed light on its contribution to cognition and neurological diseases.The RSC is particularly vulnerable to the paradoxical neurotoxic effect of non-competitive antagonist of the NMDA receptor (e.g., MK801; Olney et al. 1991). Interestingly, in rats the neurotoxic effect of MK801 is sexually dimorphic and strongly modulated by gonadal hormones (Bueno et al. 2003; de Olmos et al., 2008). Thus, orchiectomy dramatically enhances the neurotoxic effect of MK801 promoting overt neuronal death that is confined exclusively to layers IV-V of A29 (de Olmos et al., 2008; Sigwald et al., 2016). Taking advantage of the particular vulnerability of A29 to MK801 neurotoxicity we recently demonstrated that A29 is required for the retrieval of contextual fear memory (Sigwald et al., 2016). Here, we further analyzed the role of RSC in fear memory processing evaluating the expression of immediate early genes cFos and Egr-1 in RSC and areas implicated in fear memory.