What is the nature of involvement of the amygdalas basal nucleus in contextual fear conditioning?

Abstract

The amygdala is involved in emotional learning and memory, including fear conditioning. It includes several nuclei with distinct hodology. The basal nucleus (BA) receives information processed in the hippocampal formation. This latter brain region is believed to create an integrated representation of the stimuli of an environment and thus to be involved in contextual (including spatial) learning and memory. Congruent with this hodological evidence, BA selective damage results in behavioral impairments similar to those found after hippocampal damage. Rats with BA damage exhibit performance impairments in contextual, but not auditory, fear conditioning tasks (Onishi and Xavier, 2010). These results allow to discard interpretations that ascribe to the BA a role in the expression of the fear response. This study aimed at evaluating the nature of the contribution of the BA for acquisition and/or retrieval of contextual fear conditioning. We will evaluate to which extent the BA is required for (1) the acquisition an integrated representation of the stimuli of an environment, (2) the association between this context and the aversive stimulus, and/or (3) the retrieval of the fear conditioning. This will be achieved by associating topic micro-infusion of muscimol, for temporary inactivation of the BA, with each of those three stages of fear conditioning, by using a Context Preexposure Facilitation Effect (CFPE) task, a variant of the fear conditioning task. This will allow identification of the BA contribution for these processes. (AU)