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Journal of General Internal Medicine Feb 2010
Topics: Cesarean Section; Dreams; Female; Humans; Medicine in Literature; Pregnancy; Sterilization, Tubal
PubMed: 19904574
DOI: 10.1007/s11606-009-1174-7 -
Philosophical Transactions of the Royal... Feb 2021Metacognitive reflections on one's current state of mind are largely absent during dreaming. Lucid dreaming as the exception to this rule is a rare phenomenon; however,...
Metacognitive reflections on one's current state of mind are largely absent during dreaming. Lucid dreaming as the exception to this rule is a rare phenomenon; however, its occurrence can be facilitated through cognitive training. A central idea of respective training strategies is to regularly question one's phenomenal experience: is the currently experienced world , or just a dream? Here, we tested if such lucid dreaming training can be enhanced with dream-like virtual reality (VR): over the course of four weeks, volunteers underwent lucid dreaming training in VR scenarios comprising dream-like elements, classical lucid dreaming training or no training. We found that VR-assisted training led to significantly stronger increases in lucid dreaming compared to the no-training condition. Eye signal-verified lucid dreams during polysomnography supported behavioural results. We discuss the potential mechanisms underlying these findings, in particular the role of synthetic dream-like experiences, incorporation of VR content in dream imagery serving as memory cues, and extended dissociative effects of VR session on subsequent experiences that might amplify lucid dreaming training during wakefulness. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
Topics: Dreams; Humans; Virtual Reality
PubMed: 33308070
DOI: 10.1098/rstb.2019.0697 -
Sleep Mar 2015To evaluate the frequency, determinants and sleep characteristics of lucid dreaming in narcolepsy.
OBJECTIVE
To evaluate the frequency, determinants and sleep characteristics of lucid dreaming in narcolepsy.
SETTINGS
University hospital sleep disorder unit.
DESIGN
Case-control study.
PARTICIPANTS
Consecutive patients with narcolepsy and healthy controls.
METHODS
Participants were interviewed regarding the frequency and determinants of lucid dreaming. Twelve narcolepsy patients and 5 controls who self-identified as frequent lucid dreamers underwent nighttime and daytime sleep monitoring after being given instructions regarding how to give an eye signal when lucid.
RESULTS
Compared to 53 healthy controls, the 53 narcolepsy patients reported more frequent dream recall, nightmares and recurrent dreams. Lucid dreaming was achieved by 77.4% of narcoleptic patients and 49.1% of controls (P < 0.05), with an average of 7.6±11 vs. 0.3±0.8 lucid dreams/ month (P < 0.0001). The frequency of cataplexy, hallucinations, sleep paralysis, dyssomnia, HLA positivity, and the severity of sleepiness were similar in narcolepsy with and without lucid dreaming. Seven of 12 narcoleptic (and 0 non-narcoleptic) lucid dreamers achieved lucid REM sleep across a total of 33 naps, including 14 episodes with eye signal. The delta power in the electrode average, in delta, theta, and alpha powers in C4, and coherences between frontal electrodes were lower in lucid than non-lucid REM sleep in spectral EEG analysis. The duration of REM sleep was longer, the REM sleep onset latency tended to be shorter, and the percentage of atonia tended to be higher in lucid vs. non-lucid REM sleep; the arousal index and REM density and amplitude were unchanged.
CONCLUSION
Narcolepsy is a novel, easy model for studying lucid dreaming.
Topics: Adolescent; Adult; Arousal; Case-Control Studies; Cataplexy; Dreams; Dyssomnias; Female; Hallucinations; Humans; Interviews as Topic; Male; Mental Recall; Narcolepsy; Self Report; Sleep Paralysis; Sleep Stages; Sleep, REM; Young Adult
PubMed: 25348131
DOI: 10.5665/sleep.4516 -
PloS One 2022Memories of the past help us adaptively respond to similar situations in the future. Originally described by Schacter & Addis in 2007, the "constructive episodic...
Memories of the past help us adaptively respond to similar situations in the future. Originally described by Schacter & Addis in 2007, the "constructive episodic simulation" hypothesis proposes that waking thought combines fragments of various past episodes into imagined simulations of events that may occur in the future. This same framework may be useful for understanding the function of dreaming. N = 48 college students were asked to identify waking life sources for a total of N = 469 dreams. Participants frequently traced dreams to at least one past or future episodic source (53.5% and 25.7% of dreams, respectively). Individual dreams were very often traced to multiple waking sources (43.9% of all dreams with content), with fragments of past memory incorporated into scenarios that anticipated future events. Waking-life dream sources are described in terms of their phenomenology and distribution across time and sleep stage, providing new evidence that dreams not only reflect the past, but also utilize memory in simulating potential futures.
Topics: Computer Simulation; Dreams; Humans; Sleep Stages
PubMed: 35316266
DOI: 10.1371/journal.pone.0264574 -
PloS One 2020Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those...
Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural organization of dream reports is lacking, and traditional measures that distinguish REM and non-REM dreaming may be confounded by report length. This problem is amenable to the analysis of dream reports as non-semantic directed word graphs, which provide a structural assessment of oral reports, while controlling for individual differences in verbosity. Against this background, the present study had two main aims: Firstly, to investigate differences in graph structure between REM and non-REM dream reports, and secondly, to evaluate how non-semantic directed word graph analysis compares to the widely used measure of report length in dream analysis. To do this, we analyzed a set of 133 dream reports obtained from 20 participants in controlled laboratory awakenings from REM and N2 sleep. We found that: (1) graphs from REM sleep possess a larger connectedness compared to those from N2; (2) measures of graph structure can predict ratings of dream complexity, where increases in connectedness and decreases in randomness are observed in relation to increasing dream report complexity; and (3) measures of the Largest Connected Component of a graph can improve a model containing report length in predicting sleep stage and dream report complexity. These results indicate that dream reports sampled after REM awakening have on average a larger connectedness compared to those sampled after N2 (i.e. words recur with a longer range), a difference which appears to be related to underlying differences in dream complexity. Altogether, graph analysis represents a promising method for dream research, due to its automated nature and potential to complement report length in dream analysis.
Topics: Adolescent; Adult; Dreams; Female; Humans; Linear Models; Male; Mental Recall; Sleep Stages; Sleep, REM; Time Factors; Young Adult
PubMed: 32701992
DOI: 10.1371/journal.pone.0228903 -
Consciousness and Cognition Aug 2020Information processing during sleep is active, ongoing and accessible to engineering. Protocols such as targeted memory reactivation use sensory stimuli during sleep to...
Information processing during sleep is active, ongoing and accessible to engineering. Protocols such as targeted memory reactivation use sensory stimuli during sleep to reactivate memories and demonstrate subsequent, specific enhancement of their consolidation. These protocols rely on physiological, as opposed to phenomenological, evidence of their reactivation. While dream content can predict post-sleep memory enhancement, dreaming itself remains a black box. Here, we present a novel protocol using a new wearable electronic device, Dormio, to automatically generate serial auditory dream incubations at sleep onset, wherein targeted information is repeatedly presented during the hypnagogic period, enabling direct incorporation of this information into dream content, a process we call targeted dream incubation (TDI). Along with validation data, we discuss how Dormio and TDI protocols can serve as tools for controlled experimentation on dream content, shedding light on the role of dreams in the overnight transformation of experiences into memories.
Topics: Adult; Creativity; Dreams; Equipment Design; Female; Humans; Male; Memory Consolidation; Sleep Stages; Wearable Electronic Devices; Young Adult
PubMed: 32480292
DOI: 10.1016/j.concog.2020.102938 -
European Review For Medical and... Apr 2021The aim of this study was to review the available findings on sex-related differences for sleep disorders, dreams and nightmares. (Review)
Review
OBJECTIVE
The aim of this study was to review the available findings on sex-related differences for sleep disorders, dreams and nightmares.
MATERIALS AND METHODS
We explored the PubMed, EMBASE and Google Scholar electronic databases, with regards to the searching terms 'sleep', 'dreams', and 'nightmares' associated with 'sex' and/or 'gender'. Moreover, other supplementary terms for the searching strategy were 'chronobiology', and 'circadian rhythm'. Due to the relative paucity of studies including separate analysis by sex, and especially to their wide heterogeneity, we decided to proceed with a narrative review, highlighting the sex-related findings of each topic into apposite boxes.
RESULTS
On one hand, sleep disorders seem to be more frequent in women. On the other hand, sex-related differences exist for either dreams or nightmares. As for the former, differences make reference to dream content (men: physical aggression, women family themes), self-reported perspective (men dream in third person, women in first person), dream sharing (more frequent in women), lucid dreaming (women more realistic, men more controlled), and daydreaming (young men more frequently have sexual themes). Nightmares are more frequent in women too, and they are often associated with sleep disorders and even with psychiatric disorders, such as depression and/or anxiety. In women, a strong association has been shown between nightmares and evening circadian preference.
CONCLUSIONS
For many years, and for many reasons, laboratory experiments have been conducted mainly, if not exclusively, on male animals. Thus, a novel effort towards a new governance of scientific and research activities with a gender-specific perspective has been claimed for all areas of medicine, and more research on sex-differences is strongly needed also on this topic.
Topics: Dreams; Female; Humans; Male; Sex Factors; Sleep; Sleep Wake Disorders
PubMed: 33877669
DOI: 10.26355/eurrev_202104_25559 -
British Medical Journal Dec 1976
Topics: Dreams; Humans; Sleep, REM
PubMed: 188518
DOI: No ID Found -
Scientific Reports Oct 2020Why 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...
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 awakenings with recalled vs. no recall of dreams using the EEG microstate approach. This approach characterizes transiently stable brain states of sub-second duration that involve neural networks with nearly synchronous dynamics. We found that two microstates (3 and 4) dominated during NREM sleep compared to resting wake. Further, within NREM sleep, microstate 3 was more expressed during periods followed by dream recall, whereas microstate 4 was less expressed. Source localization showed that microstate 3 encompassed the medial frontal lobe, whereas microstate 4 involved the occipital cortex, as well as thalamic and brainstem structures. Since NREM sleep is characterized by low-frequency synchronization, indicative of neuronal bistability, we interpret the increased presence of the "frontal" microstate 3 as a sign of deeper local deactivation, and the reduced presence of the "occipital" microstate 4 as a sign of local activation. The latter may account for the occurrence of dreaming with rich perceptual content, while the former may account for why the dreaming brain may undergo executive disconnection and remain asleep. This study demonstrates that NREM sleep consists of alternating brain states whose temporal dynamics determine whether conscious experience arises.
Topics: Adult; Aged; Brain; Brain Mapping; Dreams; Electroencephalography; Female; Humans; Male; Mental Recall; Middle Aged; Nerve Net; Polysomnography; Rest; Sleep, Slow-Wave; Wakefulness; Young Adult
PubMed: 33051536
DOI: 10.1038/s41598-020-74075-z -
Neuroscience 1991Following a set of studies concerning the intrinsic electrophysiology of mammalian central neurons in relation to global brain function, we reach the following... (Review)
Review
Following a set of studies concerning the intrinsic electrophysiology of mammalian central neurons in relation to global brain function, we reach the following conclusions: (i) the main difference between wakefulness and paradoxical sleep lies in the weight given to sensory afferents in cognitive images; (ii) otherwise, wakefulness and paradoxical sleep are fundamentally equivalent brain states probably subserved by an intrinsic thalamo-cortical loop. From this assumption, we conclude that wakefulness is an intrinsic functional realm, modulated by sensory parameters. In support of this hypothesis, we review morphological studies of the thalamocortical system, which indicate that only a minor part of its connectivity is devoted to the transfer of direct sensory input. Rather, most of the connectivity is geared to the generation of internal functional modes, which may, in principle, operate in the presence or absence of sensory activation. These considerations lead us to challenge the traditional Jamesian view of brain function according to which consciousness is generated as an exclusive by-product of sensory input. Instead, we argue that consciousness is fundamentally a closed-loop property, in which the ability of cells to be intrinsically active plays a central role. We further discuss the importance of spatial and temporal mapping in the elaboration of cognitive and perceptual constructs.
Topics: Afferent Pathways; Animals; Awareness; Brain; Cell Membrane; Cerebral Cortex; Cognition; Consciousness; Dreams; Electroencephalography; Hallucinations; Humans; Mammals; Models, Neurological; Models, Psychological; Neurons; Perception; Sensation; Sensory Thresholds; Sleep; Sleep, REM; Thalamus; Wakefulness
PubMed: 1754050
DOI: 10.1016/0306-4522(91)90075-y