John S. Antrobus

Dreaming in the Late Morning: Summation of REM and Diurnal Cortical Activation

Since the discovery that the characteristics of dreaming sleep are far stronger in Stage 1 rapid eye movement (REM) sleep than in any other biological state, investigators have attempted to determine the relative responsibility of the tonic versus the phasic properties of REM sleep for the different characteristics of dreaming--features such as the amount of information in the dream report, the brightness and clarity of the visual images, shifts in thematic continuity, and incongruities of image and meaning. The present experiment is designed to identify dream characteristics that are specifically associated with tonic changes in level of cortical activation within sleep. It samples reports of imagery and thought during spontaneous variations within one phase of the 24-h diurnal rhythm and across the REM-NREM (non-REM) sleep cycle in order to identify the independent and joint contributions of the two cycles to imagery and thought. The rising phase of the diurnal cycle in the late night and morning was estimated from clock time during the late night and early morning and was varied by delaying the sleep onset and waking time of the subjects. Considered together with other studies, the results suggest that the major determinant of vivid visual imagery and enhanced cognitive activity during sleep is a pattern of subcortical and cortical activation that is common to both the REM phase of the REM-NREM cycle and the activated phase of the 24-h diurnal wake-sleep cycle.

Motivation and affect in REM sleep and the mentation reporting process.

Although the emotional and motivational characteristics of dreaming have figured prominently in folk and psychoanalytic conceptions of dream production, emotions have rarely been systematically studied, and motivation, never. Because emotions during sleep lack the somatic components of waking emotions, and they change as the sleeper awakens, their properties are difficult to assess. Recent evidence of limbic system activation during REM sleep suggests a basis in brain architecture for the interaction of motivational and cognitive properties in dreaming. Motivational and emotional content in REM and NREM laboratory mentation reports from 25 participants were compared. Motivational and emotional content was significantly greater in REM than NREM sleep, even after controlling for the greater word count of REM reports.

How does the dreaming brain explain the dreaming mind

Recent work on functional brain architecture during dreaming provides invaluable clues for an understanding of dreaming, but identifying active brain regions during dreaming, together with their waking cognitive and cognitive functions, informs a model that accounts for only the grossest characteristics of dreaming. Improved dreaming models require cross discipline apprehension of what it is we want dreaming models to “explain.” [Hobson et al.; Neilsen; Revonsuo; Solms]

The effect of presemantic acoustic adaptation on semantic "satiation"

A decrement in the strength of the meaning of a word after rapid repetition of that word has been called “semantic satiation.” This study asked whether this “satiation” might be produced by presemantic acoustic adaptation. Category words were utilized to prime the meaning of target words. The adaptation or “satiation” procedure, 30 rapid repetitions of the primes, was compared with a control condition of 3 repetitions. Participants listened to a series of prime words, each repeated by either the same speaker or many speakers, and then made semantic decisions on target words. When all the repetitions of a prime word are produced by the same speaker, presemantic and semantic repetitions are confounded. When the repetitions are produced by different speakers, presemantic acoustic repetition is abolished. A semantic decrement was detected with single-speaker, but not with multiple-speaker, repetitions of prime words. This study concluded that the semantic “satiation” observed here was a decrement in the activation level of semantic representations induced by presemantic acoustic adaptation.

EEG asymmetry and sleep mentation during REM and NREM

The hypothesis that dreaming is mediated by the right hemisphere was evaluated by monitoring EEG power asymmetry during REM and NREM sleep, and obtaining mentation reports when short-term temporal shifts in the EEG indicated relative left- or right-hemispheric dominance. Content analyses provided no support for the right-hemisphere hypothesis; indeed, some scales showed higher content during relative left-hemispheric dominance. In contrast to earlier reports, no difference between REM and NREM in EEG asymmetry was observed.

Cortical arousal and mentation in sleeping and waking subjects.

Cognitive variables and cortical arousal levels were examined in order to determine whether differences in cortical arousal levels within REM and waking could account for different aspects of mentation derived from the two states. Cognitive variables were derived from mentation reports collected from 30 subjects in both the waking state and after being awakened from REM sleep. Mentation reports were independently scored on seven content rating scales, by two judges blind to the conditions. These scales include among others, Total Recall Count (TRC), a count of all words in which the subject described his/her experience during the previous interval. The EEG activity, obtained from left and right midtemporoparietal and central sites, was recorded for 5-min periods before obtaining mentation reports. The absolute power of the EEG activity was calculated for each of six bandwidths. EEG power data from both waking and REM were entered into multiple linear regression equations to predict TRC. No relationships were found between TRC and general cortical activation, as measured by the EEG. Other statistical analyses, including relationships between EEG and scales of visual imagery, are discussed.

A New Beginning for Empirical Dream Research

William Domhoffs The Scientific Study of Dreams breaks new ground in the field, not by proposing grandiose, premature answers to questions about the nature of dreams but rather by showing us with unprecedented clarity and scope where we have erred in the past and allowing us to start over again. In a careful, reasoned critique, Domhoff demonstrates the shortcomings of the dominant dream theories that haunted the last century. Based on a thorough examination of converging evidence from neurophysiological, cognitive, and content analysis approaches to the study of dreams, he then lays the groundwork for the construction of future theories of the dreaming process from a neurocognitive perspective. Although a new, complete theory is not presented here, its insightful and unbiased as sessment of where dream research stands at this time should make The Scientific Study of Dreams required reading for everyone interested an empirical approach to understanding dreaming. With the publication of Freuds Interpretation ofDreamsin 1900, popular thought about the nature of dreams became centered around the idea that our dreams are disguised wishes originating from unconscious influences in early childhood. Dreams allowed us to hallucinatorily gratify socially unacceptable wishes repressed in our unconscious, and the transformative process of dreamwork ensured that these themes were well enough disguised in our dream content to allow us to sleep through the night, without being startled awake. Until the early 1950s, this psychoanalytic conception dominated dream psychology and was explored largely using the same techniques of clinical observation that led Freud to the formula tion of his original theory. The modem era of empirical research on dreaming was kicked off in the 1950s with Aserinsky and Kleitmans (1953) groundbreaking discovery of rapid eye movement (REM) sleep. As a graduate student working on a summer project, Eugene Aserinsky serendipitously discovered that about every 90 min throughout the night, humans go through short periods during which their eyes dart back and forth underneath their eyelids, accompanied by dramatic increases in brain activity as measured by electroencephalography. Soon it was reported that sub jects were much more likely to report a dream when awakened from REM sleep