Dream Features Research Articles

Cognitive structure associated with the lucid features of gamers dreams.

Cognitive structure associated with the lucid features of gamers dreams.

Neurobiology and clinical implications of lucid dreaming

Several lines of evidence converge to the idea that rapid eye movement sleep (REMS) is a good model to foster our understanding of psychosis. Both REMS and psychosis course with internally generated perceptions and lack of rational judgment, which is attributed to a hyperlimbic activity along with hypofrontality. Interestingly, some individuals can become aware of dreaming during REMS, a particular experience known as lucid dreaming (LD), whose neurobiological basis is still controversial. Since the frontal lobe plays a role in self-consciousness, working memory and attention, here we hypothesize that LD is associated with increased frontal activity during REMS. A possible way to test this hypothesis is to check whether transcranial magnetic or electric stimulation of the frontal region during REMS triggers LD. We further suggest that psychosis and LD are opposite phenomena: LD as a physiological awakening while dreaming due to frontal activity, and psychosis as a pathological intrusion of dream features during wake state due to hypofrontality. We further suggest that LD research may have three main clinical implications. First, LD could be important to the study of consciousness, including its pathologies and other altered states. Second, LD could be used as a therapy for recurrent nightmares, a common symptom of depression and post-traumatic stress disorder. Finally, LD may allow for motor imagery during dreaming with possible improvement of physical rehabilitation. In all, we believe that LD research may clarify multiple aspects of brain functioning in its physiological, altered and pathological states.

Dreaming and the Default Mode Network

This article makes a brief contribution to the ongoing dialogue on dreams between neuroscience and psychoanalysis by linking several converging lines of evidence. Recent evidence indicates that the default mode network (DMN), a highly interconnected set of “hubs” in the brain, is active during sleep. In addition, activity in the DMN is strongly associated with mental imagery that is not directly tied to current perception (“stimulus-independent thought”), which is also a central feature of dreams. Finally, the elimination of dreams is correlated with lesions in areas that have a high degree of overlap with two regions of the DMN, the ventromedial prefrontal cortex (vmPFC) and the temporo-occipital junction. Given that the vmPFC is a key node in brain circuitry regulating motivation, these converging lines of evidence support the basic psychoanalytic idea that dreams arise from wishful impulses and other emotional motivations.

In your dreams

A visit to the land of nod takes your mind on fabulous adventures. What shapes them, asks David Robson

Dream features in the early stages of Parkinson’s Disease

Few studies have investigated the relation between dream features and cognition in Parkinson's disease (PD), although vivid dreams, hallucinations and cognitive decline have been proposed as successive steps of a pathological continuum. Our objectives were therefore to characterize the dreams of early stage PD and to study the relation between dream characteristics, cognitive function, motor status, depression, dopaminergic treatment, and the presence of REM sleep behaviour disorder (RBD) and hallucinations. Dreams of 19 male PD patients and 21 matched control subjects were classified according to Hall and van de Castle system. h statistics was used to compare the dream content between patients and controls. We tested the relation between patients' dreams characteristics and cognitive function (Frontal assessment battery (FAB) and Mini-Mental State Examination tests) depression (Beck depression inventory), motor function (UPDRS), dopaminergic treatment, the presence of RBD (according to clinical criteria) and hallucinations, using general linear model statistics. Patients and controls differed only on FAB scores. Relevant differences in the Hall and van de Castle scale were found between patient's dreams and those of the control group, regarding animals, aggression/friendliness, physical aggression, befriender (higher in the patient group) and aggressor and bodily misfortunes (lower in the patient group) features. Cognitive and particularly frontal dysfunction had a significant influence on the frequency of physical aggression and animal related features, while dopaminergic doses, depressive symptoms, hallucinations and RBD did not. We found a pattern of dream alteration characterized by heightened aggressiveness and the presence of animals. These were related to more severe frontal dysfunction, which could be the origin of such changes.

Sleep architecture and sleep-related mentation in securely and insecurely attached people

Based on REM sleep's brain activation patterns and its participation in consolidation of emotional memories, we tested the hypothesis that measures of REM sleep architecture and REM sleep-related mentation would be associated with attachment orientation. After a habituation night in a sleep lab, a convenience sample of 64 healthy volunteers were awakened 10 minutes into a REM sleep episode and 10 minutes into a control NREM sleep episode in counterbalanced order, then asked to report a dream and to rate themselves and a significant other on a list of trait adjectives. Relative to participants classified as having secure attachment orientations, participants classified as anxious took less time to enter REM sleep and had a higher frequency of REM dreams with aggression and self-denigrating themes. There were no significant differences across attachment groups in other measures of sleep architecture or in post REM-sleep awakening ratings on PANAS subscales reflecting mood and alertness. Selected aspects of REM sleep architecture and mentation appeared to be associated with attachment orientation. We suggest that REM sleep plays a role in processing experiences and emotions related to attachment, and that certain features of sleep and dreaming reflect attachment orientations.

Amygdala and hippocampus volumetry and diffusivity in relation to dreaming

Microstructural analyses by MRI brain scans and by DTI analysis of MR images were used to investigate the possible relationship between deep gray matter structures (amygdala and hippocampus) and dreaming in healthy subjects. Thirty-four subjects ranging in age 20s to 70s underwent to a MRI protocol for the assessment of volume and mean diffusivity (MD) in the amygdala and hippocampus and were asked to fill out a dream diary via audiotape recording upon morning awakening for two weeks. Multiple regression analyses evaluated the relationships between anatomical measures and quantitative and qualitative measures of the reported dreams. The main result points to a dissociation between some quantitative and qualitative aspects of dream reports. While the mean number of dreams recalled per day did not show any significant relationship with the neuroanatomical measures, significant associations with some qualitative features of the recalled dreams (emotional load, bizarreness, and vividness) and, to some extent, with the length of dream reports were observed. Particularly, a higher MD of the left amygdala, reflecting a decreased microstructural integrity, was associated with shorter dream reports and lower scores on emotional load. Bizarreness of dream reports was negatively correlated with the left amygdala volume and positively correlated with the right amygdala MD. Some specific, although weaker, relationships were also found between bizarreness and hippocampal measures. These findings indicate some direct relationships between volumetric and ultrastructural measures of the hippocampus-amygdala complex and specific qualitative features of dreaming.

SPOKOJNY SEN KLITAJMESTRY ALBO CZEGO „BRAK” W EURYPIDESOWEJ „ELEKTRZE"

Peaceful dream of Clytemnestra, or what is missing in Euripides’ Electra Clytemnestra’s dream features as an important element of the vengeance dramas of both Aeschylus and Sophocles: still, is remains absent from the Euripidean version. This short essay sketches the possible implications of such an ‘omission’, while simultaneously highlighting the highly contrasting implications of the dream in the Choephorae and in the Sophoclean Electra.

Lucid dreaming: a state of consciousness with features of both waking and non-lucid dreaming.

The goal of the study was to seek physiological correlates of lucid dreaming. Lucid dreaming is a dissociated state with aspects of waking and dreaming combined in a way so as to suggest a specific alteration in brain physiology for which we now present preliminary but intriguing evidence. We show that the unusual combination of hallucinatory dream activity and wake-like reflective awareness and agentive control experienced in lucid dreams is paralleled by significant changes in electrophysiology. 19-channel EEG was recorded on up to 5 nights for each participant. Lucid episodes occurred as a result of pre-sleep autosuggestion. Sleep laboratory of the Neurological Clinic, Frankfurt University. Six student volunteers who had been trained to become lucid and to signal lucidity through a pattern of horizontal eye movements. Results show lucid dreaming to have REM-like power in frequency bands delta and theta, and higher-than-REM activity in the gamma band, the between-states-difference peaking around 40 Hz. Power in the 40 Hz band is strongest in the frontal and frontolateral region. Overall coherence levels are similar in waking and lucid dreaming and significantly higher than in REM sleep, throughout the entire frequency spectrum analyzed. Regarding specific frequency bands, waking is characterized by high coherence in alpha, and lucid dreaming by increased delta and theta band coherence. In lucid dreaming, coherence is largest in frontolateral and frontal areas. Our data show that lucid dreaming constitutes a hybrid state of consciousness with definable and measurable differences from waking and from REM sleep, particularly in frontal areas.

Homeostatic and Circadian Influences on Dreaming: NREM Mentation During a Short Daytime Nap

It has long been known that dream recall, along with various other features of dreaming, changes as a function of time of night. Yet the processes which might account for these time-dependent variations remain obscure. Here we assess the contribution of homeostatic and circadian factors to the generation of NREM mentation across the diurnal cycle. Assuming that previously reported time-of-night mentation effects are primarily driven by a circadian activation cycle which approximates the core body temperature (CBT) rhythm, it was hypothesized that more content would be reported from daytime nap awakenings as compared to night awakenings. Afternoon Nap reports were compared to previously-collected nocturnal reports from Circadian Nadir and Late Morning time points. Contrary to our hypotheses, both amount of mentation reported and propensity to report any mentation at all were lower in Nap as compared to Late Morning reports. A purely circadian influence following the CBT cycle is inadequate to explain this pattern of mentation production.

Is Television Traumatic?: Dreams, Stress, and Media Exposure in the Aftermath of September 11, 2001

The terrorist attacks of September 11, 2001, were traumatic for people living throughout the United States. It has been suggested that people living far from the attacks experienced increased stress because of their exposure to the terrorist events via the media, particularly via television. Following a traumatic or stressful event, individuals may have dreams that reflect that experience. As part of a course on dreaming, individuals recorded their dreams both prior to and following the terrorist attacks of September 11, 2001. On September 12, these same individuals reported their activities and media exposure the previous day. Results revealed (a) changes in dream features following the attacks and (b) a strong relation between exposure to the events on television and changes in dream features after the attacks. Because of the study's within-subjects design, the results provide evidence for a direct association between television viewing and subsequent increases in stress and trauma.

Complex hallucinations in waking suggest mechanisms of dream construction

Waking hallucinations suggest mechanisms of dream initiation and maintenance. Visual association cortex activation, yielding poorly attended-to, visually ambiguous dream environments, suggests conditions favoring hallucinosis. Attentional and visual systems, coactivated during sleep, may generate imagery that is inserted into virtual environments. Internally consistent dreaming may evolve from successive, contextually evoked images. Fluctuating arousal and context-evoked imagery may help explain dream features.

Chronobiological features of dream production.

A review of the scientific literature clarifies several chronobiological features of dreaming. The literature supports the conclusions that dreaming 'intensity' and, to a lesser extent dream-like quality, is modulated by (1) a sinusoidal, 90-min ultradian oscillation, (2) a 'switch-like' circadian oscillation, (3) a 12-h circasemidian rhythm, and (4) a 28-day circatrigintan rhythm (for women). Further, access to dream memory sources appears to be modulated by (5) a 7-day circaseptan rhythm. Further study of these rhythmic influences on dreaming may help to explain diverse and often contradictory findings in the dream research literature, to clarify relationships between dreaming and waking cognitive processes, to explain relationships between disturbed phase relationships and dream disturbances and to shed new light on the problems of dreaming's functions and biological markers. Further chronobiological studies of dreaming will likely enable the development of theoretical models that explain how interactions between and within major levels of oscillation determine the variable characteristics of dreaming.

Roger Ivar Lohmann, ed. Dream Travelers: Sleep Experiences and Culture in the Western Pacific. New York: Palgrave Macmillan, 2003. 246 pp.

Dream Travelers is a collection of essays focusing on Western Pacific societies that weaves together new theoretical insights and richly detailed ethnographic analyses on dreams as travels. The result is a fascinating and impressively coherent volume. Recognizing that dreams in most societies are considered to represent actual travels of the human soul across temporal, spatial, and spiritual planes, the contributors take as their starting point questions about the social/political, cosmological/religious, and personal/psychological consequences of this assumption in eleven societies scattered across Melanesia, Aboriginal Australia, and Indonesia. Lohmann's introduction provides an informative historical overview of the social science literature on dreams, and then confronts methodological and epistemological problems that have long-stymied those whose interests in dreams are more cultural than psychoanalytical. These problems stem from the widely accepted notion that dreams are more problematic than other kinds of experiences because they are personal/private/internal and can only be made social/public through narrative. Dreams, so it goes, can only be known in a limited, biased, and filtered way. But, as Kracke reminds us in his Afterword, the inability to directly share experience or verify their content is not a unique feature of dreams, but extends to all sorts of social and cultural phenomena. More importantly for the volume's authors, these assumptions a bias in anthropological thinking about dreams as mere (often bizarre) imaginings of the individual, rather than as actual travel experiences that are fundamentally important to social, political, and religious life.

A "small-world" network hypothesis for memory and dreams.

Memories are associated to one another and to the environmental cues that accompanied the events that gave rise to them. Thus, a memory is more likely to be recalled (reconstructed) if it is strongly connected to a particular environment. We propose that memory associations form a "small-world" network. According to this hypothesis, one memory might lead to the recall of an apparently unrelated memory because they are actually connected by only a few steps. This small-world hypothesis might also be relevant to the peculiar features of dreaming.

The “problem” of dreaming in NREM sleep continues to challenge reductionist (two generator) models of dream generation

The “problem” of dreaming in NREM sleep continues to challenge models that propose a causal relationship between REM mechanisms and the psychological features of dreaming. I suggest that, ultimately, efforts to identify correspondences among multiple levels of analysis will be more productive for dream theory than attempts to reduce dreaming to any one level of analysis.[Hobson et al. ; Nielsen]

Features of night dreams at neurotic disorders in children and adolescents

Peculiarities of night dreams of 78 children and adolescents (aged 10-17) with different variants of neurotic conditions and of 25 healthy ones of the same age were studied. Dreams at neurotic disorders differ as compared with ones of the healthy persons by affective and cognitive activation, timely and space "easiness", some imperative tendencies ("channelling" of colour perception, repeated dreams). Study of dreams adds significantly to а clinical characteristic of neurotic conditions, opens supplementary perspectives for investigation regularity of their pathogenesis.

Dream features in psychiatric patients on multiple psychoactive drugs.

An investigation into dreams was conducted in 100 subjects involving 50 psychiatric in-patients and fifty normal volunteers with the help of a questionnaire. The dream patterns of the two groups were compared. Results revealed that dreams of the patients were different from normal individuals even before the onset of psychiatric illness. The dreams in normal subjects were mostly related to present life situations whereas, the dreams of the patients were less frequent in this respect. On the other hand, frightening dreams, repetitive dreams and vision of snakes in the dreams were more frequent in patients. These differences became more conspicuous with the onset of illness. The dreams were suppressed in 78% patients after the institution of drug therapy. Most of the patients were getting three to four psychoactive drugs which alter the sleep pattern and may therefore affect the dreaming process. Thus, the qualitative changes in dreams of a person may serve as an early warning for an impending future illness. The suppressant effect of psychoactive drugs on dreams demands further investigations.

Eyelid Movements and Mental Activity at Sleep Onset

The nature and time course of sleep onset (hypnagogic) mentation was studied in the home environment using the Nightcap, a reliable, cost-effective, and relatively noninvasive sleep monitor. The Nightcap, linked to a personal computer, reliably identified sleep onset according to changes in perceived sleepiness and the appearance of hypnagogic dream features. Awakenings were performed by the computer after 15 s to 5 min of sleep as defined by eyelid quiescence. Awakenings from longer periods of sleep were associated with (1) an increase in reported sleepiness, (2) a decrease in the length of mentation reports, (3) a decrease in the frequency of reports of normal, wake-like thoughts, (4) an increase in the frequency of “unusual thoughts,” and (5) increased frequencies of formal dream features, including visual hallucination, self-representation, fictive movement, narrative plot, and bizarreness. While sleep-onset reports can include all features of rapid eye movement (REM) dream reports, the number of such features is markedly reduced at sleep onset, suggesting that this mentation is a greatly diminished version of REM dreaming.

How the brain goes out of its mind

Dreaming is characterized by formal visual imagery (akin to hallucination), by inconstancy of time, place and person (akin to disorientation), by a scenario-like knitting together of disparate elements (akin to confabulation) and by an inability to recall (akin to amnesia). Taken together, these four dream features are similar to the delirium of organic brain disease. By studying the brain during rapid-eye-movement (REM) sleep--the phase of sleep in which most dreaming occurs--we can begin to understand its basis in the altered neurophysiology of REM.