Sleep
September 4, 2020
R. Bottary, G. Simonelli, T. Cunningham et al.
The COVID-19 pandemic and associated lockdowns altered sleep patterns globally. Early evidence indicates that sleep duration and quality changed during the initial phases of the pandemic, likely due to shifts in socially and occupationally imposed demands. The authors note that these lifestyle and schedule changes prompted sleep researchers and clinicians to monitor sleep and sleep-related behaviors during this unprecedented period.
Sleep
August 12, 2020
Carlo Cipolli, Fabio Pizza, Claudia Bellucci et al.
People with narcolepsy type 1 recalled detailed dream experiences after 75% of naps that included sleep onset REM periods (SOREMPs) and after 25% of naps without REM sleep. Story-grammar analysis showed that dreams from daytime SOREMP naps are organized as hierarchically ordered sequences of events, called dream-stories, which are longer and more complex in the first and fourth SOREMP naps and comparable in structure to dreams from nighttime REM sleep. This similar structural organization suggests that the cognitive processes underlying dreaming are highly, though not uniformly, effective during daytime SOREMP sleep, and investigating these dreams may clarify links between brain physiology and psychological processes in REM dreaming.
Sleep
May 27, 2020
P Zendels, S Barngrover, H Peach
Among 275 adults from the United States and Thailand, mindfulness predicted both nightmare distress and sleep quality, while nightmare distress predicted poorer sleep quality. A statistical trend suggested lucid dreaming may increase nightmare distress. Lucid dreaming was linked to worse sleep quality only for individuals with low mindfulness; for those with average or high mindfulness, a zero effect could not be ruled out. The findings suggest that lucid dreaming alone may not reduce nightmare distress, but combining lucid dreaming with mindfulness practices could lower distress and improve sleep quality.
Sleep
January 13, 2020
Borbála Blaskovich, Richárd Reichardt, Ferenc Gombos et al.
People with frequent nightmares show an imbalance between sleep-protective and wake-promoting brain activity, according to a comparison of 22 nightmare participants and 22 healthy controls. Nightmare participants had less slow-wave sleep and increased high-frequency (beta and gamma) power during NREM sleep and the transition into REM sleep. Differences in low- and high-frequency power across pre-REM to post-REM transitions also distinguished the groups. Increased high-frequency power before REM was mainly driven by PTSD symptom intensity, whereas decreased low-frequency activity occurred regardless of PTSD severity. The findings suggest reduced sleep-protective activity and increased hyperarousal in nightmare participants.
Sleep
June 11, 2019
Kiyohide Usami, Anna Korzeniewska, Riki Matsumoto et al.
The sleep/wake cycle alters how neural activity spreads across large-scale brain networks. Using single-pulse electrical stimulation in patients with intracranial EEG electrodes, the study found that patterns of neural propagation at high-gamma frequencies (80-150 Hz) differ between wakefulness and sleep stages. During slow-wave sleep, frontal lobe stimulation produced greater propagation toward the parietal lobe than during wakefulness. During REM sleep, propagation decreased within the frontal lobe and increased within the parietal lobe. These directional biases in large-scale cortical network dynamics during REM sleep may help explain some unique experiential aspects of that sleep stage. The findings suggest that conscious awareness and sleep regulation involve changes in the balance of neural propagation across frontal-parietal networks.
Sleep
August 1, 2017
Kiyohide Usami, Riki Matsumoto, Katsuya Kobayashi et al.
Cortical excitability to external input differs between phasic and tonic rapid eye movement (REM) sleep. Single-pulse electrical stimulation applied directly to the cortex of seven patients with epilepsy elicited a transient increase in high gamma activity (100–200 Hz), a proxy for cortical excitability, followed by suppression. Suppression was stronger during both phasic and tonic REM than during wakefulness, but suppression during phasic REM was weaker than during tonic REM. Corticocortical evoked potentials, a measure of connectivity, did not differ between the two REM periods. The shift in cortical excitability during phasic REM toward wakefulness may produce incomplete short bursts of consciousness, contributing to dreams.
Sleep
February 1, 2014
This analysis examines the themes and content of idiopathic nightmares and bad dreams, identifying common patterns such as threats, fear, and helplessness. The findings suggest that these dreams often involve scenarios of being chased, attacked, or experiencing natural disasters, with emotional responses of terror and anxiety. The study highlights the prevalence of negative themes and the potential psychological impact of such dreams, indicating a need for further research into their origins and effects on mental health.
Sleep
February 1, 2014
Erin J. Wamsley, Claire E H M Donjacour, Thomas E Scammell et al.
A distinctive feature of narcolepsy, termed 'dream delusions,' occurs when patients mistake the memory of a vivid dream for a real experience and form sustained false beliefs that can persist for days or weeks. In interviews with 46 narcolepsy patients with cataplexy and 41 healthy controls at academic medical centers in Boston and Leiden, dream delusions were surprisingly common and often severe, differing from fleeting hypnagogic or hypnopompic hallucinations. These false memories suggest source memory deficits in narcolepsy that have not yet been fully characterized.
Sleep
February 1, 2013
Laura Mantoan, Sofia H Eriksson, Angus P Nisbet et al.
A 43-year-old woman experienced nocturnal episodes of pain and screaming that began at age 30, with no childhood or family history of parasomnia. Events occurred in the first half of the night within two hours of sleep onset, gradually increased in frequency, and were partially forgotten. Clinical and polysomnographic evaluation diagnosed adult-onset sleep terrors, excluding seizures and periodic limb movements as triggers. Mild sleep-disordered breathing was noted but of debatable significance. Brain and spine imaging ruled out lesions or neuropathies. Treatments with clonazepam, paroxetine, or gabapentin were poorly tolerated and ineffective, while trazodone worsened episodes. This is the first report of hypnopompic psychic pain linked to a NREM parasomnia, possibly representing a sensory hallucination analogous to visual hypnopompic hallucinations.
Sleep
January 1, 2010
Erin J. Wamsley, Karen Perry, Ina Djonlagic et al.
During light NREM sleep, people's dream reports often replay recent waking experiences. In a visuomotor learning task, 30% of verbal reports collected from sleeping participants related to the task. The replay became more abstracted from the original experience as sleep progressed. These findings suggest that memory reactivation during sleep is reflected in subjective dream content, offering a window into cognitive processing in the sleeping brain.
Sleep
December 1, 2009
Tore Nielsen, Connie Svob, Don Kuiken
Dream-enacting behaviors—such as speaking, crying, smiling, and moving during sleep—are common in healthy young adults, with prevalence rising from 36% to 98% depending on how specifically questions are asked. Women report more speaking, crying, fear, and smiling or laughing during dreams, while men report more sexual arousal. These gender differences persist even after accounting for other sleep disorders and dream recall. The behaviors are largely independent of other parasomnias like sleepwalking or nightmares, except for dream-talking, which is linked to sleep-talking. They are not related to alexithymia but are moderately tied to absorption. Social desirability does not affect reporting.
Sleep
September 1, 2009
Sarah Laxhmi Chellappa, Mirjam Münch, Katharina Blatter et al.
Dream recall declines with age, and this decline is linked to a weakened circadian rhythm of REM sleep. In a 40-hour nap protocol, 17 young (20–31 years) and 15 older (57–74 years) healthy volunteers reported fewer dreams after naps scheduled during the biological day, especially among older subjects. The number of dreams varied across the circadian cycle and between age groups, with older subjects recalling fewer dreams overall. No significant age differences appeared in the emotional content of dreams. The findings suggest that age-related changes in the circadian modulation of REM sleep contribute to reduced dream recall.
Sleep
March 1, 2009
Katrina Stuart, Russell Conduit
Auditory stimulation during REM sleep increases EEG arousal, decreases the amplitude and frequency of eye movements, and reduces the frequency of visual imagery reports upon awakening. These findings support theories linking ponto-geniculo-occipital (PGO) waves to dream reporting in humans.
Sleep
June 1, 1992
T Takeuchi, A Miyasita, Y Sasaki et al.
A sleep interruption schedule—waking normal subjects after 40 minutes of NREM sleep—produced sleep-onset REM periods (SOREMPs) 71.9% of the time and successfully elicited isolated sleep paralysis (ISP) in 9.4% of interruptions. Nearly all ISP episodes occurred from SOREMP, showing a close link. During ISP, subjects reported inability to move while aware of their surroundings, and most experienced auditory or visual hallucinations and unpleasant emotions. Polysomnography revealed a dissociated REM/W stage with abundant alpha EEG and persistent muscle atonia. ISP differs from lucid dreaming, nocturnal panic attacks, and REM sleep behavior disorder.
Sleep
August 1, 1989
A Brylowski, L Levitan, S LaBerge
In a single proficient lucid dreamer who signaled lucidity with eye movements, H-reflex amplitude was more suppressed during lucid REM sleep than during nonlucid REM. Greater suppression correlated with increased eye movement density, heart rate, and respiration rate. These findings indicate that lucid dreaming occurs during unequivocal REM sleep, not a state near waking, and is associated with phasic REM activation.
Sleep
June 1, 1986
C H Schenck, S R Bundlie, M G Ettinger et al.
Four men aged 67-72 with histories of injuring themselves or their spouses during sleep, often while enacting dreams, and a woman with disruptive but nonviolent sleep behaviors all showed REM sleep pathology on polysomnography: loss of chin muscle atonia, increased limb twitching, and elevated REM eye movements. Videotaped behaviors included punches, kicks, and dream movements. Slow-wave sleep was elevated for age; harmful behaviors did not occur during non-REM sleep. Four patients had serious neurological disorders (olivo-ponto-cerebellar degeneration, Guillain-Barré syndrome, subarachnoid hemorrhage, atypical dementia). Clonazepam and desipramine suppressed the behaviors, which returned when drugs were stopped. These REM sleep disorders replicate findings from cats with pontine lesions and offer insights into human behavior and dream phenomenology.
Sleep
January 1, 1986
S Purcell, J Mullington, A Moffitt et al.
Dreaming can involve self-reflection, and this ability varies by sleep stage and can be trained. Greater self-reflectiveness occurred in REM dreams compared to stages 2 and 4 sleep, which did not differ. People who frequently recalled dreams showed more self-reflectiveness than low-frequency recallers. After three weeks of home dream collection, experimental groups trained with mnemonic techniques showed more self-reflective and lucid dreaming than a baseline group. The findings suggest dreaming exists along a continuum of self-reflective awareness, supporting the view that dreaming is a higher-order cognitive activity rather than a derivative process.
Sleep
January 1, 1984
J H Herman, M Erman, R Boys et al.
During REM sleep, the direction of eye movements recorded by electrooculograph (EOG) corresponds to the direction of gaze shifts in dream imagery. In a double-blind experiment, subjects were awakened after predominantly horizontal or vertical eye movements. Dream reports were scaled for gaze shifts and compared with EOG measurements. Analyses of variance showed statistically significant relationships between the number and direction of gaze shifts in dreams and the corresponding EOG, when accounting for experimenters' prediction confidence. However, judges could not correctly match dream narratives to EOG recordings better than chance, though they did pair narratives with recordings sharing the same axis of gaze.