Research SquareOctober 14, 2026Océane Lüthi, Vincent Rochas, Audrey Theux et al.
preprint
Abstract Post-traumatic stress disorder is frequently associated with post-traumatic nightmares, which may be related to cortical hyperarousal. Imagery Rehearsal Therapy is the first-line treatment for nightmares. Targeted Memory Reactivation, which reactivates specific memories during sleep to enhance memory consolidation, has been shown to enhance the effects of Imagery Rehearsal Therapy in...
Why do we dream? Evolutionary theories suggest that dreams may confer a fitness advantage by simulating real-world challenges. Simulation-based models suggest that dreams serve adaptive functions, including resolving emotional stress and enhancing readiness for waking encounters. From this perspective, evidence of evolutionary pressures reflected in dream content would support the view that...
Magneto/electroencephalography (M/EEG) studies of dreaming are an essential paradigm in the investigation of neurocognitive processes of human consciousness during sleep, but they are limited by the number of observations that can be collected per study. Dream research also involves substantial methodological and conceptual variability, which poses problems for the integration of results. To...
According to some theories of emotion regulation, dreams could modify negative emotions and ultimately reduce their intensity. We introduce here the idea of cathartic dream, a specific and separate type of emotional dream, which is characterized by a dynamic plot with emotional twists, and where negative emotions are expressed and ultimately decreased. This process would reflect psychological...
The function of dreams is a longstanding scientific research question. Simulation theories of dream function, which are based on the premise that dreams represent evolutionary past selective pressures and fitness improvement through modified states of consciousness, have yet to be tested in cross-cultural populations that include small-scale forager societies. Here, we analyze dream content...
Magneto/electroencephalography (M/EEG) studies of dreaming are an essential paradigm in the investigation of neurocognitive processes of human consciousness during sleep, but they are limited by the number of observations that can be collected per study. Dream research also involves substantial methodological and conceptual variability, which poses problems for the integration of results. To...
Nightmare disorder (ND) is characterized by dreams with strong negative emotions occurring during rapid eye movement (REM) sleep. ND is mainly treated by imagery rehearsal therapy (IRT), where the patients are asked to change the negative story line of their nightmare to a more positive one. We here used targeted memory reactivation (TMR) during REM sleep to strengthen IRT-related memories and...
Background: Nightmare disorder (ND) is characterized by dreams with strong negative emotions occurring during rapid-eye movement (REM) sleep. ND is mainly treated by imagery rehearsal therapy (IRT), where the patients are asked to change the negative story line of their nightmare to a more positive one. Methods: We used targeted memory reactivation (TMR) during REM sleep to strengthen...
Summary: Functional dissociations in the brain observed during non-rapid eye movement (NREM) sleep have been associated with reduced information integration and impaired consciousness that accompany increasing sleep depth. Here, we explored the dynamical properties of large-scale functional brain networks derived from transient brain activity using functional magnetic resonance imaging. Spatial...
Why do people sometimes report that they remember dreams, while at other times they recall no experience? Despite the interest in dreams that may happen during the night, it has remained unclear which brain states determine whether these conscious experiences will occur and what prevents us from waking up during these episodes. Here we address this issue by comparing the EEG activity preceding...
Nightmares are characterized by the experience of strong negative emotions occurring mainly during REM sleep. Some people suffer from nightmare disorder, which is defined by the repeated occurrence of nightmares and by significant distress in wakefulness. Yet, whether frequent nightmares relate to a general increase in emotional reactivity or arousal during sleep remains unclear. To address...
Based on past literature, it is here supported that insomnia, and parasomnias such as sleepwalking, sleep terrors and nightmares, reflect an evolutionary survival mechanism, which has threat-related origins and which, in some vulnerable individuals, becomes persistent due to failure of a fear extinction function. Genetic determinants, personality traits and sleep disturbances seem to determine...
Thoughts occur during wake as well as during dreaming sleep. Using experience sampling combined with high-density EEG, we investigated the phenomenal qualities and neural correlates of spontaneously occurring thoughts across wakefulness, non-rapid eye movement (NREM) sleep, and REM sleep. Across all states, thoughts were associated with activation of a region of the midcingulate cortex....
Consciousness never fades during waking. However, when awakened from sleep, we sometimes recall dreams and sometimes recall no experiences. Traditionally, dreaming has been identified with rapid eye-movement (REM) sleep, characterized by wake-like, globally 'activated', high-frequency electroencephalographic activity. However, dreaming also occurs in non-REM (NREM) sleep, characterized by...
BACKGROUND: We previously suggested that abnormal sleep behaviors, i.e., as found in parasomnias, may often be the expression of increased activity of the reward system during sleep. Because nightmares and sleepwalking predominate during REM and NREM sleep respectively, we tested here whether exploratory excitability, a waking personality trait reflecting high activity within the mesolimbic...
Philosophers, psychiatrists and neuroscientists have all expressed interest in and formulated hypotheses on the nature of hallucinations, but no sufficient integration of these models exists to this date. The objective of this article is to present a neurophilosophical model of psychosis linking the neurobiology with the phenomenology of hallucinations and delusions. It is proposed that...
A scientific study of consciousness should take into consideration both objective and subjective measures of conscious experiences. To this date, very few studies have tried to integrate third-person data, or data about the neurophysiological correlates of conscious states, with first-person data, or data about subjective experience. Inspired by Morel's invention (Casares, 1940), a literary...
Recent studies in sleep and dreaming have described an activation of emotional and reward systems, as well as the processing of internal information during these states. Specifically, increased activity in the amygdala and across mesolimbic dopaminergic regions during REM sleep is likely to promote the consolidation of memory traces with high emotional/motivational value. Moreover, coordinated...
Vincent Rochas, Kevin Mammeri, Laurence Bayer et al.
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Previous studies on the neural correlates of dreaming using high-density EEG (hdEEG) and the serial awakening paradigm have identified posterior brain regions related to dreaming, with maximal activity over occipital areas. Based on these results, we have hypothesized that neural activity during dreaming is mainly driven by sensory experiences (e.g., vision, audition), which predominate our...