Retrosplenial cortex and fear conditioned memory

GENOUD M, GIACHERO M, SIGWALD E, DE OLMOS S, MOLINA V, LORENZO A

Huerta Grande

Congreso; Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2013

Sociedad Argentina de Investigación en Neurociencia

We have recently developed a non-invasive protocol to induce acute degeneration of neurons in deeper layers of the granular subdivision of the retrosplenial cortex (RSG) of adult male rats. The protocol is based on the high vulnerability of layer IV RSG (RSG-IV) neurons to systemic applications of MK801, a highly specific non-competitive NMDA-antagonist. MK801-induced degeneration of RSG-IV neurons is sexually dimorphic and strongly modulated by gonadal hormones; therefore it is enhanced by orchiectomy and prevented by testosterone. Here we used different MK801-treatments to address the participation of RSG-IV neurons in contextual fear conditioned memory. Interestingly, we found MK801-treatments that induce loss of RSG-IV neurons significantly impair contextual fear conditioned memory. On the contrary, treatments with MK801 that do not promote degeneration of RSG-IV neurons have no effect contextual fear conditioned memory. Moreover, unconditioned fear response is not affected by MK801-treatments. Altogether, these observations support the participation of RSG-IV neurons in anatomo-functional circuits of contextual fear conditioned memory