Inge Strauch

Sleep deprivation: effect on sleep stages and EEG power density in man.

Sleep was analysed in 8 young adults subjects during two baseline nights and two recovery nights following 40.5 h sleep deprivation. Sleep stages were scored from the polygraph records according to conventional criteria. In addition, the EEG records of the entire nights were subjected to spectral analysis to compute the frequency distribution of the power density in the 0.25-25 Hz range for 0.5 Hz or 1.0 Hz bins. In the first recovery night, the power density in the delta band was significantly higher than baseline for total sleep time as well as for sleep stages 2, 3 and 4, 4 and REM. These changes were not restricted to the delta band, but extended to higher frequency bands. Minor, but significant, effects of sleep deprivation were seen in the power density distribution of the second recovery night. In the baseline nights, a progressive reduction of power density in the delta/theta range was present for successive non-REM-REM sleep cycles for total sleep time and stages 2, 3 and 4, and 4. The results show that effects of sleep deprivation as well as trends within the sleep periods are readily apparent from spectral analysis, but are inadequately reflected by conventional sleep scoring. When the power density values were integrated over the entire frequency range (0.75-25 Hz) for each non-REM-REM sleep cycle, an exponential decline from cycle 1 to cycle 3 was suggested. The present findings support the hypothesis that the EEG power density in the low frequency range is an indicator of a progressively declining process during sleep whose initial value is determined by the duration of prior waking.

Psychobiology of altered states of Consciousness

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.

A single dose of benzodiazepine hypnotics alters the sleep EEG in the subsequent drug-free night.

All-night spectral analysis of the sleep EEG was used to study the effect and after-effect of a single bedtime dose of flunitrazepam (2 mg), flurazepam (30 mg) or triazolam (0.5 mg) in healthy young males. In the night of drug treatment all 3 hypnotics reduced the EEG slow waves and enhanced the activity in the frequency range of sleep spindles. In the subsequent drug-free night, the latter changes were no longer present after triazolam, whereas the reduction of slow wave activity persisted after all compounds.

The Home Dreams and Waking Fantasies of Boys and Girls Between Ages 9 and 15: A Longitudinal Study

In this longitudinal developmental study, 12 boys and 12 girls provided home dreams and waking fantasies at 3 age levels: 9–11, 11–13, and 13–15. A total of 299 dreams and 286 fantasies were coded by 2 independent raters using Hall and Van de Castle (1966) content categories. In addition, word counts and bizarreness ratings were completed. There were very few changes in the dreams or waking fantasies of either boys or girls, but dream reports were longer at ages 13–15, the aggression/friendliness percent increased over the course of the study, joint-sex peer groups became more frequent, and girls showed a decline in animal percent. The tendency in a wide range of societies for men to dream mostly about other men and for women to dream equally of women and men was found in both the dreams and waking fantasies. Dreams and fantasies differed markedly, with dreams containing more outdoor and unfamiliar settings, and more bizarreness. In dreams the children tended to portray themselves as victims of aggression and recipients of friendliness, but in fantasies they took a more active role as aggressors and befrienders. It is suggested that the children in this study portrayed themselves in their dreams as they conceived of themselves in everyday life, while in their waking fantasies they imagined themselves as they would have liked to be.