Brain reactivity to emotion persists in NREM sleep and is associated with individual dream recall.
Cerebral cortex communications January 1, 2022 Maëva Moyne, Guillaume Legendre, Luc Arnal et al.
The brain's ability to detect emotional signals persists during non-rapid eye movement (NREM) sleep. Using electroencephalography, neural responses to emotional voices differed from neutral voices both while awake and during NREM sleep. Emotional voices also triggered more EEG arousals (sleep perturbations) than neutral or control stimuli. The amplitude of sleep event-related potentials and the number of arousals after emotional voices increased linearly with how often participants recalled their dreams. Similar correlations with dream recall frequency appeared for beta and sigma brain oscillations, but not for theta. No such correlations were found for neutral or control stimuli. These findings suggest that emotion-specific neural reactivity during sleep, rather than general alertness, may contribute to encoding or retrieving dreams.