Mechanisms of Amygdala-Mediated Memory Enhancement in Humans

Direct electrical stimulation (DES) of the basolateral complex of the amygdala (BLA) can improve declarative memory, reflecting the role of the BLA in modulating memory processes in medial temporal lobe (MTL) regions as a function of emotional arousal. Thus, DES can reveal mechanisms of BLA-mediated memory enhancement relevant to human mental health and disease. DES of the BLA can be used to interrogate the function of memory circuits, especially how neuronal oscillations in the MTL support declarative memory. First, BLA is hypothesized to wield the capacity to prioritize long-term retention of information initially encountered adjacent in time over days and weeks after encoding. Second, the BLA preferentially projects to anterior MTL regions and thus is hypothesized to preferentially modulate memory processes in those anatomic regions, processes thought to support memory for non-spatial items more so than memory for spatial locations. Third, although emotional arousal, amygdala activity, MTL activity, and memory performance are typically correlated, the investigators hypothesize that DES will reveal that BLA outputs to other MTL regions cause improved memory performance by directly eliciting pro-memory oscillatory states in those networks. The expected outcomes represent a significant advancement for the basic science of normal memory function and significant movement towards novel therapeutics designed to emulate endogenous mechanisms of memory enhancement.