Fear in dreams and in wakefulness: Evidence for day/night affective homeostasis

Abstract

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 electroencephalography (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.

Pandemic dreams: quantitative and qualitative features of the oneiric activity during the lockdown due to COVID-19 in Italy

“…Beyond confirming the hypothesized impact of both daily emotional experience and sleep pattern on the oneiric activity during the lockdown also considering its emotional features, such finding can also be considered in light of the hypothesis that dreams may have a role in emotional processing and memory consolidation [ 53 ]. Dreaming activity and emotional regulation share similar neurobiological processes, suggesting the existence of a continuum between waking and REM sleep activity in several areas like amygdala, hippocampus and medial prefrontal cortex [ 18 , 20 , 24 , 72 , 70 ]. Consistently, it has been proposed that dreams may represent an offline simulation of threatening events, working as problem-solving based emotional coping strategies for the rehearsal of threat-avoidance skills, sustained by the activation of amygdalocortical networks associated with fear (Revonsuo, 200; [ 51 ].…”

“…Consistently, it has been proposed that dreams may represent an offline simulation of threatening events, working as problem-solving based emotional coping strategies for the rehearsal of threat-avoidance skills, sustained by the activation of amygdalocortical networks associated with fear (Revonsuo, 200; [ 51 ]. Other authors propose a role for dreams in fear extinction [ 45 , 70 ], emotional conflict resolution, and reduction of negative mood [ 10 ]. Beyond the specific focus of these theoretical models, they all suggest that fear in dreams should be related to more adaptive behaviours in response to daily threatening stimuli [ 53 ].…”

“…Beyond the specific focus of these theoretical models, they all suggest that fear in dreams should be related to more adaptive behaviours in response to daily threatening stimuli [ 53 ]. Interestingly, a recent paper showed higher activation of insula and midcingulate cortex in dreams containing fear, and in a second study that subjects reporting a higher incidence of fear in their oneiric activity exhibited during wakefulness a decreased emotional arousal and fMRI response to adverse stimuli in the insula, amygdala and midcingulate cortex [ 70 ]. Consistently, the spread of negative emotions in lockdown-dreams may be the expression of a preparatory process to address the threats represented by the pandemic, aimed at the promotion of more adaptive behaviours during daily life.…”

Microsurgical resection of fronto-temporo-insular gliomas in the non-dominant hemisphere, under general anesthesia using adjunct intraoperative MRI and no cortical and subcortical mapping: a series of 20 consecutive patients

“…Fear was the least well-identified emotion (53%). Recent researches, including functional MRI, reported that the insular cortex plays a main role in the identification and reaction to fear 34 , 35 . Complex mental and cognitive states accurately was attributed in 85% of cases.…”

Do all mammals dream?

“…Investigating cortical activity during non-REM, REM and SI in the rock hyrax with high density electroencephalography, as employed by Siclari et al (2017) in humans which is predictive of dreams in humans, or other methods under development in humans to understand dream content (e.g. Horikawa, Tamaki, Miyawaki, & Kamitani, 2013;Sterpenich, Perogamvros, Tononi, & Schwartz, 2019), may augment our understanding of the neural correlates of consciousness in humans and across mammals as a class. The comparative observations regarding the physiology of sleep, and by extensions dreams, in mammals thus provides not only interesting observations for thought experiments, but also reveals potentially informative model species that may rapidly increase our current understanding of the manner in which the brain produces, processes, and accesses conscious experiences.…”