Reduced sleep time is associated with increases in frontal sleep-like activity and emotion regulation failures

INTRODUCTION: Emotion self-regulation relies both on cognitive and behavioral strategies implemented to modulate the subjective experience and/or the behavioral expression of a given emotion. OBJECTIVES: While it is known that a network encompassing fronto-cingulate and parietal brain areas is engaged during successful emotion regulation, the functional mechanisms underlying failures in emotion suppression are still unclear. METHODS: We analyzed facial-view video and high-density EEG recordings of nineteen healthy adult subjects (26±3yrs, 10F) during an emotion suppression (ES) and a free expression (FE) task performed on two consecutive days. An actigraph was worn for 7-days and used to determine sleep-time before each experiment. Changes in facial expression were identified and manually marked on the video recordings. Continuous hd-EEG recordings were preprocessed using standard approaches to reduce artifactual activity and source-modeled using sLORETA. RESULTS: Changes in facial expression during ES, but not FE, were preceded by local increases in sleep-like activity (1-4Hz) in in brain areas responsible for emotional suppression, including bilateral anterior insula and anterior cingulate cortex, and in right middle/inferior frontal gyrus (p<0.05, corrected; Figures 1 and 2). Moreover, shorter sleep duration the night prior to the ES experiment correlated with the number of behavioral errors (p=0.01; Figure 3) and tended to be associated with higher frontal sleep-like activity during emotion suppression failures (p=0.05). CONCLUSIONS: These results indicate that local sleep-like activity may represent the cause of emotion suppression failures in humans, and may offer a functional explanation for previous observations linking lack of sleep, changes in frontal activity and emotional dysregulation. DISCLOSURE: No significant relationships.