Role of Rapid Eye Movement Sleep in Waking Emotional Processing

Abstract

Brain imaging studies have revealed that brain regions related to emotions, such as the ventromedial prefrontal cortex (vmPFC) and amygdala, are activated during rapid-eye-movement (REM) sleep. In addition, the pre-REM negativity (PRN), a brain potential indicated by current source density analysis to originate from the vmPFC and amygdala, appears before REMs during REM sleep. The hypotheses proposed on roles of emotion-related brain activation during REM sleep include the consolidation of conditioned fear and extinction, emotional memory consolidation, dissipation of emotional charge, and optimization of waking behavior in emotional responses, the last of which requires more experimental evidence. This review presents an overview of human emotion-related brain activities during REM sleep and their roles in waking emotional processing. Specifically, the hypothesis that memories of decision-making under uncertain conditions are reprocessed during REM sleep and biases the next day’s decision-making in favor of appropriate long-term choices is discussed. This hypothesis provides a framework for investigating the role of REM sleep in optimizing waking emotional behavior.