Amygdala Modulation of Hippocampal Arc Expression

DESCRIPTION (provided by applicant): The involvement of the basolateral amygdala (BLA) in emotionally-influenced memory has been known for nearly 40 years. Pharmacological, neurophysiological and anatomical evidence suggests that the BLA modulates information processing in the hippocampal system (comprised of the hippocampus proper, dentate gyrus, subiculum and entorhinal cortex) during consolidation of emotionally-influenced memory. The particular mechanisms of BLA modulation, however, remain unclear. Because expression of immediate early genes, such as Arc and zif268, during memory acquisition is necessary for normal memory consolidation, it is possible that BLA activity during memory acquisition influences training-induced Arc expression and the levels of Arc protein in the hippocampal system. The experiments in this proposal will test this hypothesis utilizing recent advances in fluorescent in situ hybridization methods, as well as traditional immunohistochemistry and immunoblot analyses. Changes in training-induced Arc expression in hippocampal neurons will be examined after BLA activity is altered by either muscimol or oxotremorine, treatments that decrease or increase BLA activity, respectively, and have been shown to modulate consolidation of emotionally-influenced memory. Additionally, I will examine the effect of altered BLA activity during memory acquisition/consolidation on hippocampal Arc expression during memory retrieval.