Stress, Sleep, and the Emotional Enhancement of Memory: An fMRI Investigation of Prioritized Encoding and Consolidation

Emotional experiences often become our strongest, longest-lasting memories. This preference for emotional information, often referred to as the emotional enhancement of memory (EEM), is magnified when stress occurs in proximity to encoding and when sleep occurs during consolidation. Recent behavioral findings suggest that stress and sleep interact to facilitate the EEM effect, which invites questions about the neural underpinnings of stress–sleep interactions in emotional memory processes. This dissertation investigated (1) the effects of pre-encoding stress on neural correlates of emotional memory encoding and (2) interactive effects of stress, encoding processes, and subsequent sleep on emotional memory consolidation. These questions were addressed using a pre-existing dataset that included a psychosocial stress manipulation, functional magnetic resonance imaging during an emotional memory task, and polysomnographic recordings during overnight sleep. Results show that stress reactivity moderates relationships between patterns of brain activity during encoding and next-day emotional memory performance. However, there was no evidence for stress–sleep interactions, as defined in the present study, on emotional memory consolidation. These findings shed light on neural networks underlying the effects of stress on the prioritized encoding of emotional information and suggest avenues for future research at the intersection of stress, sleep, and emotional memory.