Dream reports from different stages of sleep.

8 Ss (paid volunteer males, ages 17-27) were placed in the information-gathering sleep situation for 57 (nonconsecutive) nights. Ss were awakened during various stages of sleep (determined by EEG and eye movement activity), and the content of their dream or thoughts at the time of the awakening explored. Mental activity (dreaming, thinking) was reported at all levels of sleep. Reports during periods of rapid eye movement (REM) revealed more statements involving affective, visual, and muscular content with less correspondence to residue of S's waking life, than in non-REM periods. Results are related to Freudian theory of dreams. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Finger electromyographic activity during sleep: Its relation to dreaming in deaf and normal subjects.

Observations carried out during the sleep of 13 deaf Ss showed that: (a) the rates of dream recall from rapid eye movement (REM) periods were similar to those for normal hearing Ss; (b) finger electromyographic (EMG) bursts outside of REM periods were not related to the recall of mental activity; (c) in both deaf and hearing Ss, REM periods showed a consistently accelerated rate of finger EMG activity in comparison with other stages of sleep; (d) contrary to expectations, rates of finger EMG activity for 10 normal hearing Ss were just as high as those of the deaf group. The implications of this finding for the motor theory of thinking were discussed. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterns of dreaming recall: An EEG study.

11 recallers and 11 nonrecallers of dreams were compared with respect to several characteristics of their rapid eye movement (REM) periods during sleep. Continuous recordings of REMs and EEGs were obtained for 2 consecutive nights of uninterrupted sleep for each S. The records were scored to yield measures of total dream time (TDT) and rate of eye movements during REM periods. Recallers had significantly higher TDT than nonrecallers. However, contrary to prediction, nonrecallers had a significantly higher rate of REMs during dreaming than recallers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction of visual imagery during NREM sleep

In an attempt to induce eye movements (EMs) in non-rapid eye movement sleep, light and sound stimuli were presented to human subjects (at below-waking threshold) during stage 2 sleep. EMs were used as an indicator of ponto-geniculo-occipital (PGO) wave activity. When at least one concurrent EM in response to the stimuli was observed, the subjects were awakened and mentation reports collected. Compared to equivalent control periods with no stimulation, awakenings from the stage 2 stimulation condition showed a higher frequency of visual imagery reports, electroencephalogram alpha activity, and k-complexes. Additional control and stimulation conditions elicited from rapid eye movement sleep awakenings showed no significant differences in the frequency of visual imagery reports. When the amount of alpha activity before stage 2 awakenings from which imagery was reported was compared to that from which imagery was not reported, imagery awakenings showed significantly more alpha. Results can be interpreted as evidence for a link between PGO activity and dreaming in humans or in terms of an arousal-window hypothesis of visual hallucinations.     

Effects of hypnotic induction and suggestions on nocturnal dreaming and thinking.

Examined the effects of hypnotic induction and types of suggestions on sleep mentation, using 77 Ss in a 2 * 3 factorial experiment. Immediately before going to sleep at night, 1/2 of the Ss were exposed to a hypnotic induction and 1/2 were not, and all Ss were given either authoritative, permissive, or no suggestions to think and dream that night on a specific topic. Ss reported their thoughts and dreams when awakened at sleep onset and during REM and NREM periods. The intricate findings indicate that hypnotic induction and types of suggestions exerted complex effects on nocturnal thinking and dreaming. Contents of the dreams were affected by an interaction between hypnotic induction and types of suggestions, and the hypnotic induction increased the number of nocturnal thoughts which pertained to the specified topic. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Consciousness in waking and dreaming: the roles of neuronal oscillation and neuromodulation in determining similarities and differences

State-dependent aspects of consciousness are explored with particular attention to waking and dreaming. First, those phenomenological differences between waking and dreaming that have been established through subjective reports are reviewed. These differences are robustly expressed in most aspects of consciousness including perception, attention, memory, emotion, orientation, and thought. Next, the roles of high frequency neuronal oscillation and neuromodulation are explored in waking and rapid eye movement sleep, the stage of sleep with which the most intense dreaming is associated. The high frequency neuronal oscillations serve similar functions in the wake and rapid eye movement states sleep but neuromodulation is very different in the two states. The collective high frequency oscillatory activity gives coherence to spatially separate neurons but, because of the different neuromodulation, the binding of sensory input in the wake state is very different from the binding of internally perceived input during rapid eye movement sleep. An explanatory model is presented which states that neuromodulation, as well as input source and brain activation level differentiate states of the brain, while the self-organized collective neuronal oscillations unify consciousness via long range correlations.     

Dream content and adaptation to a stressful situation.

Conducted an investigation with 24 male undergraduates, 8 of whom were controls. 16 Ss slept in the laboratory for 3 nonconsecutive nights. On the 3rd night Ss saw a stressful film before going to sleep and again in the morning. Half of the Ss were presented with part of the sound track of the film during rapid eye movement (REM) periods at an intensity below the waking threshold (film-sound condition) while the other half were not (film-alone condition). The dreams of the Ss in the film-sound condition contained significantly more incorporations of film elements than those of Ss in the film-alone condition, suggesting that the presentation of the sound stimulus during REM periods was partially successful in enhancing the effects of the film on dreams. Contrary to expectations, Ss who exhibited more emotionality at the 2nd presentation of the film tended to be those who had more incorporations of film elements in their dreams; thus it appears that film incorporation interfered with the adaptation to stress. Finally, a group of Ss who saw the film twice, with an 8-hr waking interval, tended to be more anxious at the 2nd presentation than Ss who slept during the interval. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Progressive cortical synchronization of ponto-geniculo-occipital potentials during rapid eye movement sleep

Phasic events, termed ponto-geniculo-occipital potentials, appear in the brainstem, thalamus and cerebral cortex during rapid eye movement sleep. In the cat, the species of choice for ponto-geniculo-occipital studies, these field potentials are usually recorded from the lateral geniculate thalamic nucleus and visual cortex. However, the fact that brainstem cholinergic neurons play a crucial role in the transfer of ponto-geniculo-occipital potentials to the thalamus, coupled with the evidence that mesopontine tegmental neurons project to virtually all thalamic nuclei, together explain why ponto-geniculo-occipital potentials are recorded over widespread territories, beyond the visual thalamocortical system. Here we demonstrate, by means of multi-site unit and field potential recordings from sensory, motor and association cortical areas in behaving cats, that: (i) ponto-geniculo-occipital potentials appear synchronously over the neocortex; and (ii) that their cortical synchronization develops progressively from the period preceding rapid eye movement sleep by 30-90 s (pre-rapid eye movement), to reach the highest degree of intracortical coherence during later epochs of rapid eye movement sleep. We propose that the widespread coherence of cortical ponto-geniculo-occipital potentials underlies the synchronization of fast oscillations (30-40 Hz) during rapid eye movement sleep over many, functionally distinct cortical territories implicated in dreaming, as brainstem-induced ponto-geniculo-occipital-like potentials are consistently followed by such fast oscillations.     

The effects of pre-sleep suggestion upon REM sleep.

8 university students who spent 7 consecutive nights in a sleep lab were given presleep instructions on the 4th and 6th nights to either increase or decrease their dreaming time depending upon the order in which they were to receive the treatment conditions. Sleep records showed no changes from baseline sleep stage percentages, but the number of rapid eye movements (REMs) and eye movement density measures indicated increases (but not decreases) which were in accordance with the suggestions. Results cast further doubt on the equivalence of the REM state and dreaming and are in support of the notion that REMs themselves may be better indicators of dreaming than is the REM state. (French summary) (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dream deprivation and facilitation with hypnosis.

Attempted to modify sleep and dreaming through the administration of various posthypnotic suggestions. Ss were 17 male undergraduates who were selected (using the Harvard Group Scale of Hypnotic Susceptibility) for high susceptibility to hypnosis. After 2 adaptation nights, 5 Ss were given a dream-deprivation suggestion, 8 were given a suggestion of dream-facilitation, and the remaining 4 Ss were administered a neutral posthypnotic suggestion. Subjective dream reports were dramatically affected in the predicted directions. Electrophysiological changes were also noted in certain Ss, although these results were not nearly as consistent as the subjective data. The dream-deprivation group had significantly more Stage I sleep than the other 2 groups, and certain of these Ss had much less REM sleep. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The adaptive function of sleep: The differential effects of sleep and dreaming on recall.

Tested the hypothesis that REM sleep serves an adaptive function by examining the effects of sleep and dreaming vs. dream deprivation on the recall of ego-threatening or nonthreatening material. Ss were 40 undergraduates with high ego strength, as measured by the Rorschach Concept Evaluation Technique and the Psychological Insight Test. Ss were given an interrupted task paradigm under conditions which would lead to a threat to self-esteem for failed items, and were tested for recall after REM-deprivation, NREM awakening, or 2 or 10 hr. of daytime activity. Scores on the Repression-Sensitization scale were also examined in relation to ego strength and recall on the interrupted task. Results show that Ss who slept recalled neutral material better than Ss who did not sleep, and Ss who had REM sleep recalled threatening material better than those who had no opportunity to dream. It is concluded that NREM sleep facilitates retention of nonemotional material, while REM sleep deals with material containing affective components. (39 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in the extracellular matrix on the surface of sintered bovine bone implanted in the femur of a rabbit: an immunohistochemical study

The neuroanatomical substrates controlling and regulating sleeping and waking, and thus consciousness, are located in the brain stem. Most crucial for bringing the brain into a state conducive for consciousness and information processing is the mesencephalic part of the brain stem. This part controls the state of waking, which is generally associated with a high degree of consciousness. Wakefulness is accompanied by a low-amplitude, high-frequency electroencephalogram, due to the fact that thalamocortical neurons fire in a state of tonic depolarization. Information can easily pass the low-level threshold of these neurons, leading to a high transfer ratio. The complexity of the electroencephalogram during conscious waking is high, as expressed in a high correlation dimension. Accordingly, the level of information processing is high. Spindles, and alpha waves in humans, mark the transition from wakefulness to sleep. These phenomena are related to drowsiness, associated with a reduction in consciousness. Drowsiness occurs when cells undergo moderate hyperpolarizations. Increased inhibitions result in a reduction of afferent information, with a lowered transfer ratio. Information processing subsides, which is also expressed in a diminished correlation dimension. Consciousness is further decreased at the onset of slow wave sleep. This sleep is controlled by the medullar reticular formation and is characterized by a high-voltage, low-frequency electroencephalogram. Slow wave sleep becomes manifest when neurons undergo a further hyperpolarization. Inhibitory activities are so strong that the transfer ratio further drops, as does the correlation dimension. Thus, sensory information is largely blocked and information processing is on a low level. Finally, rapid eye movement sleep is regulated by the pontine reticular formation and is associated with a "wake-like" electroencephalographic pattern. Just as during wakefulness, this is the expression of a depolarization of thalamocortical neurons. The transfer ratio of rapid eye movement sleep has not yet been determined, but seems to vary. Evidence exists that this type of sleep, associated with dreaming, with some kind of perception and consciousness, is involved in processing of "internal" information. In line with this, rapid eye movement sleep has higher correlation dimensions than slow-wave sleep and sometimes even higher than wakefulness. It is assumed that the "near-the-threshold" depolarized state of neurons in the thalamus and cerebral cortex is a necessary condition for perceptual processes and consciousness, such as occurs during waking and in an altered form during rapid eye movement sleep.     

Incorporation of concern- and nonconcern-related verbal stimuli into dream content.

The hypothesis that cues related to Ss' current concerns can control attentional and cognitive processes during sleeping and dreaming was examined by presenting concern- and nonconcern-related verbal stimuli to 7 male undergraduates during sleep Stages 2 and REM. The taped dream reports were judged for stimulus incorporation by 2 independent raters. Results reveal that concern stimuli were incorporated significantly more often than nonconcern stimuli in REM, although low dream recall rates prevented assessment of whether this relationship also existed in Stage 2. This finding supports the results of other studies that indicate that responsiveness to auditory stimuli during sleeping and dreaming is largely dependent on the personal significance of the stimulus to the sleeper. It further suggests that sleeping Ss are capable of making more complex and subtle cognitive discriminations, based on the waking value of the stimulus to the S, than has previously been demonstrated. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye tracking dysfunction in schizophrenia: Characterization of component eye movement abnormalities, diagnostic specificity, and the role of attention.

To characterize oculomotor components and diagnostic specificity of eye tracking abnormalities in schizophrenia, we examined a large consecutively admitted series of psychotic patients and matched controls. The most common abnormality in schizophrenic patients was low gain (slow) pursuit eye movements (47% of cases). Pursuit and saccadic eye movement abnormalities were no more severe in schizophrenic Ss than in those with affective psychoses, except that high rates of catch-up saccades were unique to schizophrenic Ss (17% of cases). These findings indicate that impaired pursuit eye movements are a major cause of eye tracking impairments in schizophrenia, that tracking dysfunctions commonly occur in affective psychoses, and that markedly high rates of catch-up saccades during eye tracking may be specific to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Father, mother, and stranger as elicitors of attachment behaviors in infancy.

Compared fathers with mothers and strangers as elicitors of attachment behaviors in 10 male and 10 female infants from each of 3 age groups (10, 13, and 16 mo). Differential proximity-seeking behavior, distress vocalization, and stranger eye contact from a "secure base" were used to index attachment. Fathers were superior to strangers as elicitors of attachment behaviors but 2nd to mothers at all age levels. When both parents were present, Ss approached mothers twice as often as fathers. Tested with each parent separately, they traveled to the mother in a shorter time than they traveled the same distance to the father and spent more time near the mother. The amount of eye contact with strangers was greater when Ss were near mothers as compared to fathers. Distress vocalization during separation from the parents was one of the few measures which did not discriminate between mothers and fathers. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye-hand coordination: Oculomotor control in rapid aimed limb movements.

Three experiments are reported in which Ss produced rapid wrist rotations to a target while the position of their eyes was being monitored. In Experiment 1, Ss spontaneously executed a saccadic eye movement to the target around the same time as the wrist began to move. Experiment 2 revealed that wrist-rotation accuracy suffered if Ss were not allowed to move their eyes to the target, even when visual feedback about the moving wrist was unavailable. In Experiment 3, wrist rotations were equally accurate when Ss produced either a saccadic or a smooth-pursuit eye movement to the target. However, differences were observed in the initial-impulse and error-correction phases of the wrist rotations, depending on the type of eye movement involved. The results suggest that aimed limb movements use information from the oculomotor system about both the static position of the eyes and the dynamic characteristics of eye movements. Furthermore, the information that governs the initial impulse is different from that which guides final error corrections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Respiratory and body movements as indicators of sleep stage and wakefulness in infants and young children

Conventional polysomnographic (PSG) sleep staging to sleep staging based on a static-charge-sensitive bed (SCSB) recording in infants and young children was compared. The study consisted of whole-night clinical sleep studies in 22 children at 24 weeks (SD 24, range 1-79 weeks) of age. Most of the children presented with respiratory disturbances during sleep. From the SCSB record, sleep stages were differentiated according to regularity of breathing, presence of body movements, and most important, presence of high-frequency components of breathing (SCSB spikes). With both methods, three sleep/wake stages were distinguished: rapid eye movement (REM) sleep, non-rapid eye movement (NREM) sleep and wakefulness. The average interscorer reliability of the PSG sleep staging controlled in nine subjects was 88%. The average concordance between the two methods ranged from 82 to 85%, depending on the criteria used for scoring the SCSB. The mean sensitivity of the SCSB to detect NREM sleep ranged from 77 to 90% and the mean sensitivity to detect REM sleep ranged from 61 to 86%. The mean positive predictive value was 89-96% for NREM sleep and 54-67% for REM sleep. In conclusion, REM sleep is characterized by irregular breathing with superimposed fast respiratory movements. These changes are specific enough to allow distinction between episodes of NREM sleep, REM sleep and wakefulness with the non-invasive SCSB method in infants and young children. Incomplete concordance between PSG and SCSB score was most frequently observed during sleep stage transition periods, where the behavioural state and electrophysiological criteria disagreed. When combined with the PSG, the SCSB provides complementary information about the behavioural state of child.     

Duration of movements in a dial setting task as a function of the precision of manipulation.

Pertaining to the art of industrial time study practices and a more complete understanding of human manual movements, the effects of precision as a variable on movement duration was studied. "Ss were required to adjust alternately each of two dials on a control panel." 24 right handed naval enlisted men served as Ss. "The precision required to adjust each dial was systematically varied and the effects of this variation on the durations of four parts of the control movement were determined… . Results clearly demonstrated that the time taken by operators to move between adjustments depended on the precision requirements of those adjustments… . Results provide additional evidence to refute the concept that a work cycle consists of an additive combination of independent elements." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on "Smooth-pursuit eye movements: A comparison of two measurement techniques" by Lindsey, Holzman, Haberman, and Yasillo.

D. T. Lindsey et al (1978) reported that the qualitative comparability of smooth-pursuit eye movement recordings derived from EOG and infrared reflection techniques is high. When Ss were examined who displayed what P. S. Holzman et al (1978) have labeled in their schizophrenic patients a "Type II" tracking dysfunction, there was poor correspondence between the 2 methods, indicating that the spikes evident in Type II tracking do not stem from movement of the eyes. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in dream recall.

Ss who typically fail to remember dreams at home (nonreporters) and Ss who frequently remember dreams (reporters) slept in the laboratory for 4 nights each. Gradual or abrupt awakenings were made at each EEG Stage-I REM (dream) period. Although nonreporters and reporters did not differ in REM-period frequency or EEG patterns during sleep, nonreporters did report dreaming less frequently following REM-period awakenings. Ss showed self-consistency in frequency of dream reporting and in type of failure to report. Some nonreporters typically failed to remember any content; others typically said they were awake and thinking. Comparisons among reporters and sub-groups of nonreporters for eye-movement frequency, arousal threshold, and dreamlike-report content indicate that it may be useful to distinguish different kinds of nonreporters. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)