Sleep disturbance as the hallmark of posttraumatic stress disorder

The reexperiencing of a traumatic event in the form of repetitive dreams, memories, or flashbacks is one of the cardinal manifestations of posttraumatic stress disorder (PTSD). The dream disturbance associated with PTSD may be relatively specific for this disorder, and dysfunctional REM sleep mechanisms may be involved in the pathogenesis of the posttraumatic anxiety dream. Furthermore, the results of neurophysiological studies in animals suggest that CNS processes generating REM sleep may participate in the control of the classical startle response, which may be akin to the startle behavior commonly described in PTSD patients. Speculating that PTSD may be fundamentally a disorder of REM sleep mechanisms, the authors suggest several strategies for future research.

Observations on the neurophysiologic theory of acceleration (+Gz) induced loss of consciousness

The characteristics of centrifuge +Gz-induced loss of consciousness (G-LOC) have revealed a specific kinetic pattern of resulting physiologic events. The relationship of these events provides an initial basis for describing the possible neurophysiologic mechanism of G-LOC. A description of G-LOC is developed which divides the G-LOC episode into specific periods based on the psychophysiologic events that occur. Emphasis is placed on the type of acceleration profile which would be most likely to occur during inflight aerial combat maneuvering in fighter aircraft. The symptoms of myoclonic flail movements and memorable dreams which are observed in association with G-LOC may provide key information for unraveling the neurophysiologic mechanism of G-LOC and subsequent recovery. A detailed understanding of the kinetics and mechanism of G-LOC is paramount to eventually solving this critical fighter aviation related problem.

Consciousness and abilities of dream characters observed during lucid dreaming

A description of several phenomenological experiments is given. These were done to investigate of which cognitive accomplishments dream characters are capable in lucid dreams. Nine male experienced lucid dreamers participated as subjects. They were directed to set different tasks to dream characters they met while lucid dreaming. Dream characters were asked to draw or write, to name unknown words, to find rhyme words, to make verses, and to solve arithmetic problems. Part of the dream characters actually agreed to perform the tasks and were successful, although the arithmetic accomplishments were poor. From the phenomenological findings, nothing contradicts the assumption that dream characters have consciousness in a specific sense. Herefrom the conclusion was drawn, that in lucid dream therapy communication with dream characters should be handled as if they were rational beings. Finally, several possibilities of assessing the question, whether dream characters possess consciousness, can be examined with the aid of psychophysiological experiments.

Neural networks and REM sleep

The nature of certain forms of memory is discussed in relation to neural networks and REM sleep.

Recurring themes and images in a series of consecutive REM dreams

A consecutive series of REM dreams were collected from one subject over a period of four nights and examined for recurring themes and images. Analysis suggested a nonrandom pattern of dreaming consistent with the proposition that the themes and images are held as elements in a limited capacity storage system from which they can be recycled. One such system can be described by means of a simple testable mathematical model. Some of the implications of this are discussed.

The right cerebral hemisphere: emotion, music, visual-spatial skills, body-image, dreams, and awareness

Based on a review of numerous studies conducted on normal, neurosurgical and brain-injured individuals, the right cerebral hemisphere appears to be dominant in the perception and identification of environmental and nonverbal sounds; the analysis of geometric and visual space (e.g., depth perception, visual closure); somesthesis, stereognosis, the maintenance of the body image; the production of dreams during REM sleep; the perception of most aspects of musical stimuli; and the comprehension and expression of prosodic, melodic, visual, facial, and verbal emotion. When the right hemisphere is damaged a variety of cognitive abnormalities may result, including hemi-inattention and neglect, prosopagnosia, constructional apraxia, visual-perceptual disturbances, and agnosia for environmental, musical, and emotional sounds. Similarly, a myriad of affective abnormalities may occur, including indifference, depression, hysteria, gross social-emotional disinhibition, florid manic excitement, childishness, euphoria, impulsivity, and abnormal sexual behavior. Patients may become delusional, engage in the production of bizzare confabulations and experience a host of somatic disturbances such as pain and body-perceptual distortions. Based on studies of normal and "split-brain" functioning, it also appears that the right hemisphere maintains a highly developed social-emotional mental system and can independently perceive, recall and act on certain memories and experiences without the aid or active reflective participation of the left. This leads to situations in which the right and left halves of the brain sometime act in an uncooperative fashion, which gives rise to inter-manual and intra-psychic conflicts.

Panic attacks during sleep: a hyperventilation-probability model

Panic attacks during sleep are analysed in terms of a hyperventilation theory of panic disorder. The theory assumes that panic attacks during sleep are a manifestation of severe chronic hyperventilation, a dysfunctional state in which renal compensation has led to a relatively steady state of diminished bicarbonate. Reductions in respiration during deep non-REM sleep lead to respiratory acidosis which triggers hyperventilatory hypocapnea and subsequent panic. A probability model designed to predict when during sleep panic attacks are likely to occur is supported by relevant data from studies of sleep and panic attacks. Implications for treatment are discussed.

A proposed mechanism for the visions of dream sleep

The visions of dream sleep are suggested to occur through a dream mechanism which implicates tryptamine derivatives as endogenous paychedelics. The hallucinations that occur in some schizophrenic syndromes are also proposed to occur through a similar, though desynchronized, mechanism. These compounds occur in the human pineal gland and are regarded as neurotransmitters or neuroregulators. A protocol for experimental verification is suggested.

The right hemisphere in imagery, hypnosis, rapid eye movement sleep and dreaming. Empirical studies and tentative conclusions

Visual imagery, hypnosis, creativity, dreams, and "imagination" have all been linked conceptually by theoreticians of various schools to an increased influence of right hemispheric processes compared with left hemispheric processes. This paper reviews empirical studies that have addressed the issue of whether there is an increased activation or efficiency of right hemispheric processes during imagery, hypnosis, rapid eye movement sleep, and dreaming. Overall, there is considerable evidence supporting the notion of increased right hemispheric activation in imagery. There is also some evidence supporting this view for rapid eye movement sleep, dreaming, and hypnotic phenomena. For the most part, however, the lack of adequate studies, contradictory or negative findings, and moderating variables make it difficult to draw definitive conclusions at this time.

Recovery from Gz-induced loss of consciousness: psychophysiologic considerations

Eight healthy male volunteer members of the USAFSAM acceleration panel were exposed to two consecutive acceleration runs of +1 Gz to +7 Gz at 6 G.s-1 onset rates. The subjects were instructed to relax during the acceleration exposure in order to voluntarily induce loss of consciousness (LOC). The subjects were asked to relate dreams, thoughts, or other mental illusions experienced during G-LOC episodes. Most subjects were amused and surprised, as well as interested in, relating their experience, although they were embarrassed about the G-LOC episode itself. Early post-G-LOC transient paralysis, as well as late LOC myoclonic (flailing) movements, were evident. Heart-rate response to the acceleratory stress was uneventful; maximum heart rate occurred 3.2 s after the onset of LOC. The study of dreams during normal sleep stages has been reviewed by many investigators, but this research has not extended to acceleration/hypoxic types of unconsciousness where dreams also seem to occur. G-LOC dream-state analysis, post-G-LOC paralysis, and their possible repercussions upon performance and incapacitation periods should be investigated, not only as curious events, but as operationally important and psychophysiologically significant.

Dream anxiety attacks (nightmares)

Nightmares--disturbances of dreaming sleep experienced at some point in time by most patients--are often seen in adults as a consequence of physical or emotional trauma. The presence of nightmares on a chronic basis in adult life may reflect specific personality characteristics and may define a population at risk for other psychiatric disturbances. Treatment, if indicated, may include psychotherapy and pharmacotherapy, with the regimen determined by the patient's specific history and symptoms.

The thematic continuity of mental sleep experience in the same night

It has been found that the contents of mental sleep experience (MSE) in rapid eye movement (REM) sleep are often interrelated. The aim of this study was to see whether this interrelatedness is better accounted for by the hypothesis that the mental sleep experience interrupted by provoked awakening is resumed when the subject returns to sleep (resumption), or by the hypothesis that the same contents are elaborated repeatedly throughout the night (iterative processing). We also aimed to gain some information as to the processes by which contents previously stored in memory are retrieved and inserted into the current MSE. Ten subjects were awakened 4 times on each of 4 nights after 9 min of REM sleep, and the contents of all the possible pairings of reports were scored and compared with respect to the factors "night" (same/different), "report continguity" (contiguous/noncontinguous reports), "unit interrelated" (lexical/propositional), and "interrelationship" (paradigmatic/syntagmatic). Both the occurrences and the frequencies of interrelations were greater for same night pairs than for different night pairs, but without significant differences between contiguous and noncontiguous pairs: these data provide support for the iterative processing hypothesis. The units interrelated in pairs of reports are more frequently at a lexical than a propositional level and show more paradigmatic than syntagmatic interrelationships: these data suggest that the reelaboration of contents of previous MSEs occurs mainly at a local level, making for the coherence, rather than the thematic, progression of the MSE narrative.

The function of dreams (REM sleep): roles for the hippocampus, melatonin, monoamines, and vasotocin

Rapid eye movement (REM) sleep is suggested to play a role in the storage of memory, resolution of emotional experiences, and erasure of memory (forgetting). Plasticity of hippocampal physiology, morphology, and chemistry seems to be evidence for new memory formation. REM sleep, melatonin, and monoamines may be involved in the transfer of memory from the intermediate-term high-capacity buffer in the hippocampus into long-term memory storage in the neocortex. Vasotocin, which is released by melatonin, could be an amnestic agent that erases recent memory from the hippocampal-entorhinal complex during dreams.

Cerebral blood flow in normal and abnormal sleep and dreaming

Measurements of regional or local cerebral blood flow (CBF) by the xenon-133 inhalation method and stable xenon computerized tomography CBF (CTCBF) method were made during relaxed wakefulness and different stages of REM and non-REM sleep in normal age-matched volunteers, narcoleptics, and sleep apneics. In the awake state, CBF values were reduced in both narcoleptics and sleep apneics in the brainstem and cerebellar regions. During sleep onset, whether REM or stage I-II, CBF values were paradoxically increased in narcoleptics but decreased severely in sleep apneics, while in normal volunteers they became diffusely but more moderately decreased. In REM sleep and dreaming CBF values greatly increased, particularly in right temporo-parietal regions in subjects experiencing both visual and auditory dreaming.

Dreams of the rarebit fiend: neuromedical synthesis of unconscious meaning

A promising new "ecumenical" movement in psychiatry attempts to synthesize the two great intellectual traditions, psychoanalysis and neurobiology, so that we may avoid splitting the care of the patient into the partial domains of biotherapy that lacks the understanding of mental interrelations and purely psychological psychotherapy that lacks an appreciation of the embeddedness of mental processes in brain function. Recent synthetic work is assessed, taking as a point of departure an historic symposium in Pittsburgh, October 26-27, 1984, entitled "Neurobiology and the Unconscious: Psychoanalysis Looks Toward the Future." The means of representation of meaning (whose description was begun by Freud) in such unconscious material as dreams and folklore show the imprint of the brain function in which they are imbedded. Our afferent and efferent processes, including language, are patterned by their neuromedical basis. Linkages will be sought of representational images to visual, vestibular, and neuromotor traces: evidence that the human "thinking machine" is a very human body rather than some disembodied psychological self or computer simulation by artificial intelligence programming. Illustrative material is in part drawn from the popular dream episodes cartooned by Winsor McCay, which were considered graphic masterpieces, and incorporated representations of many normal unconscious brain mechanisms, including unusual perspectives, vestibular sensations, neuromotor inhibitions, transformations; visual and linguistic distortions, bizarre bodily intrusions, and sexual symbols. J. Allen Hobson and R.W. McCarley's 1977 arguments for the determining the significance of the pontine dream generator may have been anticipated by McCay's 1905 Dreams of the Rarebit Fiend in which, at the end of each very Freudian nightmare, the dreamer wakes and swears off eating welsh rarebits as if they caused all his unconscious images. To avoid a biological reductiveness, Freud, whom Sulloway (1983) has described as a biologist of the mind, resorted to presenting psychoanalysis as a pure psychology, not because he ever doubted the neurological imbeddedness of mind, but only because he felt medical psychoanalysts were too easily seduced and distracted by neurological mechanisms of his day to appreciate properly the importance of psychodynamics. Increasing recognition of the imbeddedness of psychoanalysis in brain function is now timely and likely, providing fresh directions for both medical psychoanalysis and the neurosciences.(ABSTRACT TRUNCATED AT 400 WORDS)

Dream process in asthmatic subjects with nocturnal attacks

Polygraphic sleep recordings were made and dream reports collected over 3 consecutive nights for 12 asthmatic subjects with nocturnal attacks and 12 matched normal control subjects. The asthmatic group 1) had more episodes of a vivid impression of dreaming without recollection of dream content ("white dreams") after awakening spontaneously in the morning (nights 1 and 2) and after awakening immediately following REM sleep (night 3), 2) used shorter sentences in dream narrations, and 3) had no dream recall when awakened during nocturnal asthma attacks. The authors suggest that conflictual material emerging during REM or other sleep stages may contribute to the occurrence of nocturnal attacks but is repressed on awakening.

Dreams and contemporary stress: a disruption-avoidance-adaptation model

A disruption-avoidance-adaptation model is proposed to provide a framework for understanding the seemingly disparate findings from studies of dream function. The model is based on the notion that there is an oscillation between disruption of sleep caused by dreaming about a stressful stimulus followed by an avoidance of the stimulus in order to achieve homeostasis. The oscillation is postulated to continue until there is adaptation to the disruptive stimulus. Continuity is assumed to exist between waking and sleeping experience.