Mapeamento das fontes de processamento de resíduos diurnos em sonhos

Abstract

The intricate interplay between visual perception and emotion determines how waking experience influences mental activity during sleep through a conspicuous but difficult to-predict “day residue”. Here, we set out to map the neural sources associated with visuoaffective processing of the “day residue” during hypnagogic sleep, when one transitions from a state of quiet wakefulness with eyes closed to non-REM stages 1 and 2 sleep. To do so, we assessed 28 healthy participants in a combined protocol of napping with serial awakenings, pre-sleep stimulation with affective visual imagery, combined measures of semantic similarity between reports of viewed and imagined images, affect ratings, 64 channel EEG source estimation, and functional connectivity analysis. Overall, low-frequency EEG power was associated with weaker residues, and high-frequency EEG power was associated with stronger residues. The source networks most significantly correlated with imagery and affective residues were markedly different between wake-sleep states, partially overlapping with the default mode network during N1 by up to 50% and 61%, respectively. The results allowed us to identify neural correlates of visuoaffective processing of daytime residues, showing that hypnagogic processing of waking experience involves complex, dynamic, and sequential bihemispheric interactions between multiple cortical, subcortical, and cerebellar structures with visual, limbic, optokinetic, and cognitive functions. Thus, this study contributes to filling crucial gaps in the literature on the neural correlates of consciousness, memory, and emotion, presenting new evidence on the brain mechanisms that support the emergence of mental images at the threshold between wakefulness and sleep, with implications for cognitive neuroscience, sleep psychopathology, and understanding the phenomenological nature of transient mental states.