EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations over the Right Frontal Cortex during REM Sleep and Presleep Wakefulness Predict Anger in REM Sleep Dreams

Sikka, Pilleriin; Noreika, Valdas; Valli, Katja

doi:10.1523/jneurosci.2884-18.2019

“…Future studies with a larger sample of participants should also explore whether bihemispheric tDCS during REM sleep interferes with a wider range of EEG frequencies involved in motor processing, including alpha and gamma bands as well as broadband responses 85,86 . Last but not least, our data suggest that the questionnaire that we developed is more sensitive to the tDCS induced changes than free dream reports; this is in line with findings that questionnaires are generally more sensitive to details of dream phenomenology (such as emotions) than free reports 50,51,66,87 . While the questionnaire was developed by the authors and has not yet been validated, it is open to future refinement and this would be a valuable next step.…”

Section: Frequency Of Bodily Sensations and Movement In Dreams To Sysupporting

confidence: 87%

Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement

Noreika

¹

,

Windt

²

,

Kern

³

et al. 2020

Sci Rep

Self Cite

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Recently, cortical correlates of specific dream contents have been reported, such as the activation of the sensorimotor cortex during dreamed hand clenching. Yet, despite a close resemblance of such activation patterns to those seen during the corresponding wakeful behaviour, the causal mechanisms underlying specific dream contents remain largely elusive. Here, we aimed to investigate the causal role of the sensorimotor cortex in generating movement and bodily sensations during REM sleep dreaming. Following bihemispheric transcranial direct current stimulation (tDCS) or sham stimulation, guided by functional mapping of the primary motor cortex, naive participants were awakened from REM sleep and responded to a questionnaire on bodily sensations in dreams. Electromyographic (EMG) and electroencephalographic (EEG) recordings were used to quantify physiological changes during the preceding REM period. We found that tDCS, compared to sham stimulation, significantly decreased reports of dream movement, especially of repetitive actions. Other types of bodily experiences, such as tactile or vestibular sensations, were not affected by tDCS, confirming the specificity of stimulation effects to movement sensations. In addition, tDCS reduced EEG interhemispheric coherence in parietal areas and affected the phasic EMG correlation between both arms. These findings show that a complex temporal reorganization of the motor network co-occurred with the reduction of dream movement, revealing a link between central and peripheral motor processes and movement sensations of the dream self. tDCS over the sensorimotor cortex interferes with dream movement during REM sleep, which is consistent with a causal contribution to dream experience and has broader implications for understanding the neural basis of self-experience in dreams. Dreams are vivid, often emotionally intense and narratively complex experiences occurring in sleep. In our dreams, we feel immersed in alternative worlds and have the experience of interacting with other persons and objects. Often this involves the subjective experience of moving through the dream world, and movement is among the most frequently reported dream experiences, second only to visual imagery 1,2. Yet these rich subjective experiences stand in stark contrast to the outward unresponsiveness and lack of observable behaviour during sleep. This study aimed to investigate the causal mechanisms underlying dream movement and bodily experience in dreams by applying transcranial direct current stimulation (tDCS) over sensorimotor areas. While

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“…Thus, nightmare patients would be more prone to emotional dysregulation, as suggested by one recent study reporting decreased mPFC activity during the viewing of negative pictures in these patients (Marquis et al, ). Furthermore, exerting ineffective emotional regulation strategies (e.g., fear suppression) and elevated anxiety during wakefulness may lead to increased excitability of negatively‐loaded memories at sleep‐onset or even during sleep (Malinowski, ; Schmidt & Gendolla, ; Sikka, Pesonen, & Revonsuo, ; Sikka, Revonsuo, Noreika, & Valli, ), namely in conditions where monitoring from the prefrontal cortex is reduced (Braun et al, ; Maquet et al, ). Such disruption in the regulation of emotions during wakefulness and sleep has been proposed as a major contributing factor to insomnia (Wassing et al, ).…”

Section: Discussionmentioning

confidence: 99%

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

Sterpenich

¹

,

Perogamvros

²

,

Tononi

³

et al. 2019

Human Brain Mapping

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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.

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“…Furthermore, exerting ineffective emotional regulation strategies (e.g. fear suppression) and elevated anxiety during wakefulness may lead to increased excitability of negatively-loaded memories at sleep-onset or even during sleep (Schmidt RE and GH Gendolla 2008;Malinowski J 2017;Sikka P et al 2018;Sikka P et al 2019), namely in conditions where monitoring from the prefrontal cortex is reduced (Maquet P et al 1996;Braun AR et al 1997). Such disruption in the regulation of emotions during wakefulness and sleep has been proposed as a major contributing factor to insomnia (Wassing R et al 2016).…”

Section: Discussionmentioning

confidence: 99%

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

Sterpenich

¹

,

Perogamvros

²

,

Tononi

³

et al. 2019

Preprint

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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 highdensity 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 STATEMENTHighly 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. 2000), others reported a balance of positive and negative emotions (Schredl M and E Doll 1998), or found that joy and emotions related to approach behaviors may prevail (Fosse R et al. 2001;Malcolm-Smith S et al. 2012). When performing a lexicostatistical analysis of large datasets of dream reports, a clear dissociation between dreams containing basic, mostly fear-related, emotions and those with other more social emotions (e.g. embarrassment, excitement, frustration) was found, highlighting distinct affective modes operating during dreaming, with fear in dreams representing a prevalent and biologically-relevant emotional category (Revonsuo A 2000;Schwartz S 2004). Thus, if fear-containing dreams serve an emotion regulation f...

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EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations over the Right Frontal Cortex during REM Sleep and Presleep Wakefulness Predict Anger in REM Sleep Dreams

Cited by 48 publications

References 86 publications

Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement

Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement

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

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

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