PT  - JOURNAL ARTICLE
AU  - V Sterpenich
AU  - L Perogamvros
AU  - G Tononi
AU  - S Schwartz
TI  - Fear in dreams and in wakefulness: evidence for day/night affective homeostasis
AID  - 10.1101/534099
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 534099
4099  - http://biorxiv.org/content/early/2019/05/16/534099.short
4100  - http://biorxiv.org/content/early/2019/05/16/534099.full
AB  - Recent neuroscientific theories have proposed that emotions experienced in dreams contribute to the resolution of emotional distress and preparation for future affective reactions. We addressed one emerging prediction, namely that experiencing fear in dreams is associated with more adapted responses to threatening signals during wakefulness. Using a stepwise approach across two studies, we identified brain regions activated when experiencing fear in dreams and showed that frightening dreams modulated the response of these same regions to threatening stimuli during wakefulness. Specifically, in Study 1, we performed serial awakenings in 18 participants recorded throughout the night with high-density EEG and asked them whether they experienced any fear in their dreams. Insula and midcingulate cortex activity increased for dreams containing fear. In Study 2, we tested 89 participants and found that those reporting higher incidence of fear in their dreams showed reduced emotional arousal and fMRI response to fear-eliciting stimuli in the insula, amygdala and midcingulate cortex, while awake. Consistent with better emotion regulation processes, the same participants displayed increased medial prefrontal cortex activity. These findings support that emotions in dreams and wakefulness engage similar neural substrates, and substantiate a link between emotional processes occurring during sleep and emotional brain functions during wakefulness.SIGNIFICANT STATEMENT Highly debated while pivotal to current theoretical models of dreaming, the relationship between emotion processing during wakefulness and in dreams remains elusive. In a first study, we used high-density EEG recordings and observed that regions involved in fear processing (i.e. the insula and midcingulate cortex) were activated during fear-related dreams. This first finding demonstrates that emotions in dreams engage similar neural circuits as during wakefulness. In a second study, using fMRI, we show that higher incidence of fear in dreams was associated with reduced emotional arousal and brain responses indicative of better emotion regulation during wakefulness. Together, these results strongly support the idea that experiencing fear in a secure environment, as in dreams, relates to more adapted responses to threatening events in real life.