Sleep researchers in different disciplines disagree about how fully dreaming can be explained in terms of brain physiology. Debate has focused on whether REM sleep dreaming is qualitatively different from nonREM (NREM) sleep and waking. A review of psychophysiological studies shows clear quantitative differences between REM and NREM mentation and between REM and waking mentation. Recent neuroimaging and neurophysiological studies also differentiate REM, NREM, and waking in features with phenomenological implications. Both evidence and theory suggest that there are isomorphisms between (...) the phenomenology and the physiology of dreams. We present a three-dimensional model with specific examples from normally and abnormally changing conscious states. Key Words: consciousness; dreaming; neuroimaging; neuromodulation; NREM; phenomenology; qualia; REM; sleep. (shrink)

Sleep researchers in different disciplines disagree about how fully dreaming can be explained in terms of brain physiology. Debate has focused on whether REM sleep dreaming is qualitatively different from nonREM (NREM) sleep and waking. A review of psychophysiological studies shows clear quantitative differences between REM and NREM mentation and between REM and waking mentation. Recent neuroimaging and neurophysiological studies also differentiate REM, NREM, and waking in features with phenomenological implications. Both evidence and theory suggest that there are isomorphisms between (...) the phenomenology and the physiology of dreams. We present a three-dimensional model with specific examples from normally and abnormally changing conscious states. Key Words: consciousness; dreaming; neuroimaging; neuromodulation; NREM; phenomenology; qualia; REM; sleep. (shrink)

We have investigated the emotional profile of dreams and the relationship between dream emotion and cognition using a form that specifically asked subjects to identify emotions within their dreams. Two hundred dream reports were collected from 20 subjects, each of whom produced 10 reports. Compared to previous studies, our method yielded a 10-fold increase in the amount of emotion reported. Anxiety/fear was reported most frequently, followed, in order, by joy/elation, anger, sadness, shame/guilt, and, least frequently, affection/eroticism. Unexpectedly, there was no (...) significant difference in the profiles of emotion reported by men and women. When the reports were scored for bizarreness, a significant correlation was found between the occurrence of bizarreness and major shifts in emotion. These results support the conclusion that dreaming is a mental state whose general emotional features are widely shared across individuals and strongly linked to cognitive features within individual dreams. (shrink)

The studies reported in the following articles are aimed at providing a comprehensive, detailed, and quantitative picture of cognition in human dreaming. Our main premises are that waking, REM sleep, and non-REM sleep represent physiologically distinct and identifiable brain states and that the differences between waking, REM, and NREM mentation reflect these physiological differences. We have studied dreams at a formal level of analysis and, in these papers, have studied the specific dream properties of emotions, bizarre transformations, scene shifts, and (...) plot coherence, in adults and 4- to 10-year-old children, as part of a larger effort to map state-dependent mental phenomena back onto the varying neurobiological processes that must underlie them. We believe that such efforts will enhance our understanding not only of dreaming and its neurophysiological substrates, but also of the cognitive processes that dreaming shares with other unusual mental states. (shrink)

The "Nightcap," a relatively nonintrusive and "user-friendly" sleep monitoring system, was used by 11 subjects on 10 consecutive nights in their homes. Eighty-eight sleep mentation reports were obtained after spontaneous awakenings from Nightcap-identified REM sleep and 61 were obtained from NREM awakenings. Sleep mentation was recalled in 83% of REM reports and 54% of NREM reports. The median length of REM reports was 148 words compared to 21 words for NREM reports. Twenty-four percent of the REM reports were over 500 (...) words long; no NREM reports over 500 words were obtained. REM report lengths were lowest during the first 15 min of the REM cycle and longest 15–45 min into the period. In contrast, 7 of the 9 NREM reports more than 100 words long occurred within the first 15 min of NREM periods. The Nightcap thus appears to be an effective and efficient method of collecting large numbers of sleep mentation reports with correlated sleep staging under normal ecological conditions. (shrink)

A novel "dream splicing" technique allows the objective evaluation of thematic coherence in dreams. In this study, dream reports were cut into segments and segments randomly recombined to form spliced reports. Judges then attempted to distinguish spliced reports from intact ones. Five judges correctly scored 22 spliced and intact reports 82% of the time ; 13 of the 22 reports were correctly scored by all five judges . We conclude that most dream reports contain sufficient coherence to allow judges to (...) distinguish intact from spliced reports. In contrast, abridged reports, which had all but their first and last five lines removed, were correctly identified in only 10 of 38 reports, suggesting that thematic continuity does not normally extend from the beginning to the end of dreams. The continuity identified in this minority of the reports depended on easily identifiable features, such as specific characters, objects, locations, and emotions, rather than on "latent" themes. (shrink)

To extend the hypothesis that bizarre discontinuities in dreams result from the interaction of chaotic, "bottom-up" brainstem activation with "top-down" cortical synthesis, we have performed a detailed analysis of dream discontinuities using a new methodology that allows for objective characterization of this formal dream feature. Transformations of characters and objects in dream reports were found to follow definite associational rules. While there were 11 examples of character–character transformation and 7 of inanimate object–inanimate object transformation, transformations of characters into inanimate objects (...) and vice versa were never observed. Judges′ scores on a transformation-matching task further showed that the nature of the transformed character or object is highly constrained by the features of the initial character or object . We conclude that despite the threat to dream coherence posed by bizarre discontinuities, significant coherence is maintained by associational constraints, especially in the case of object and character transformations. (shrink)

In this paper, a new method of quantitatively assessing continuity and discontinuity of visual attention is developed. The method is based on representing narrative information using graph theory. It is applicable to any type of narrative report. Since dream reports are often described as bizarre, and since bizarreness is partially characterized by discontinuities in plot, we chose to test our method on a set of dream data. Using specific criteria for identifying and arranging objects of visual attention, dream narratives from (...) 10 subjects were obtained and mapped onto graphs. The interrater reliabilities were 76% and 91% . Discontinuities in visual attention were quantified by plotting transitions from one part of a graph to another, which provided a spatiotemporal map of attention shifts within a narrative. This procedure was compared with other approaches to discontinuity and also applied to a set of 10 fantasy reports from the same subjects. The results showed that our method includes but transcends other approaches and has the capability to distinguish dream and fantasy reports. To our knowledge, the method provides the most rigorous and reliable measure to date of continuity and discontinuity of attention in narrative reports. (shrink)

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. (shrink)

The nature and time course of sleep onset 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 an increase in (...) reported sleepiness, a decrease in the length of mentation reports, a decrease in the frequency of reports of normal, wake-like thoughts, an increase in the frequency of “unusual thoughts,” and 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 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. (shrink)

We have conducted a home-based study of children′s dream reports in which parents used open-ended interviewing styles to collect 88 dream reports from their 4- to 10-year-old children in the comfortable and supportive environment of their own homes. Particular attention was paid to formal properties including characters , settings, self-representation, and bizarreness. In contrast to previous studies, our data indicate that young children are able to give long, detailed reports of their dreams that share many formal characteristics with adult dream (...) reports. Because this wide range of dream mentation is only revealed to trusted confidants in a familiar and comfortable environment, an important implication is that the sleep laboratory may not be the best source of naturalistic dream data. (shrink)

To test the notion that shifts in visual imagery and attention are correlated with experiences of emotion, we studied 10 dream reports using an affirmative probe of emotion and a quantitative measure of plot discontinuity. We found that emotion, especially changes in emotion, are correlated with discontinuities in visual imagery. These correlations are quantified using a new graph theoretical method for analyzing narrative reports.

Definitions of dreaming are not required to map formal features of mental activity onto brain measures. While dreaming occurs during all stages of sleep, intense dreaming is largely confined to REM. Forebrain structures and many neurotransmitters can contribute to sleep and dreaming without negating brainstem and aminergic-cholinergic control mechanisms. Reductionism is essential to science and AIM has considerable heuristic value. Recent findings support sleep's role in learning and memory. Emerging technologies may address long-standing issues in sleep and dream research.

By assuming that REM sleep either plays a critical role in all memory consolidation or no role in any, Vertes & Eastman have chosen to reject, rather than explain, robust experimental findings of a role for sleep in memory and learning. In contrast, Nielsen has attempted to integrate conflicting findings in the dispute over REM versus NREM mentation. Researchers must trust the data more and the theories less, and build integrative rather than exclusionary models if they hope to resolve these (...) knotty problems effectively. [Nielsen; Vertes & Eastman]. (shrink)

Sleep has long been a topic of fascination for artists and scientists. Why do we sleep? What function does sleep serve? Why do we dream? What significance can we attach to our dreams? We spend so much of our lives sleeping, yet its precise function is unclear, in spite of our increasing understanding of the processes generating and maintaining sleep. We now know that sleep can be accompanied by periods of intense cerebral activity, yet only recently has experimental data started (...) to provide us with some insights into the type of processing taking place in the brain as we sleep. There is now strong evidence that sleep plays a crucial role in learning and in the consolidation of memories. Once the preserve of psychoanalysts, 'dreaming' is now a topic of increasing interest amongst scientists. With research into sleep growing, this volume is both timely and valuable in presenting a unique study of the relationship between sleep, learning, and memory. It brings together a team of international scientists researching sleep in both human and animal subjects. Aimed at researchers within the fields of neuroscience, cognitive neuroscience, psychiatry, and neurology, this book will be an important first step in developing a full scientific understanding of the most intriguing state of consciousness. (shrink)