Showing papers on "Non-rapid eye movement sleep published in 1978"

Effects of exercise on sleep

Abstract: We tested the hypothesis that EEG sleep stages 3 and 4 (slow-wave sleep, SWS) would be increased as a function of either acute of chronic exercise. Ten distance runners were matched with 10 nonrunners, and their sleep was recorded under both habitual (runners running and nonrunners not running, 3 night) and abruptly changed (runners not running and nonrunners running, 1 night) conditions. Analyses of both visually scored SWS and computer measures of delta activity during non-rapid eye-movement (NREM) sleep failed to support the SWS-exercise hypothesis. The runners showed a significantly higher proportion and a greater absolute amount of NREM sleep than the nonrunners. The runners showed less rapid eye-movement activity during sleep than the nonrunners under both experimental conditions, indicating a strong and unexpected effect of physical fitness on this measure. Modest afternoon exercise in nonrunners was associated with a strong trend toward elevated heart rate during sleep. Mood tests and personality profiles revealed few differences, either between groups or within groups, as a function of exercise.

The relationship between changes in REM sleep and clinical improvement in depressed patients treated with amitriptyline

Abstract: EEG sleep recordings were obtained on consecutive nights from six hospitalized depressed patients before, during, and after treatment with amitriptyline for a total of 370 nights of data, about 85% of all nights of the study. Amitriptyline significantly reduced time spent in rapid eye movement (REM) sleep and prolonged the REM latency throughout the treatment period. Three patients who improved during treatment showed a REM rebound when amitriptyline was discontinued, whereas three patients who did not improve showed no REM rebound.

Effects of sleep deprivation on sleepiness, sleep intensity, and subsequent sleep in the rat.

Abstract: The effects of 24 hr of sleep deprivation on cortical EEG and ventral hippocampus EEG recordings, ventral hippocampus spike rates, sleep stages percentages, and bout length measures were studied in rats. Two groups, differing only in the rate and distance they were forced to walk during deprivation by the water wheel method, were recorded continuously (23 hr per day) for one baseline, one deprivation, and two recovery days. During deprivation, microsleeps, increased hippocampal spike rates, and increased amplitude of the EEG recordings all suggested the intrusion of sleep processes. Nonetheless, there was no evidence to support the idea that these animals were not substantially deprived of sleep. No important differences were found in the recovery data of the two groups, even though one group walked three times as far as the other during deprivation. This supports the idea that, in conjunction with large amounts of sleep deprivation, changes in exercise and energy depletion may have little effect on sleep measures. During recovery, increased hippocampal spike rates and bout lengths, as well as increases in EEG amplitude, were interpreted in terms of increased sleep "intensity." High amplitude NREM sleep rebounded first, followed by rebounds in both paradoxical sleep and low amplitude NREM sleep. This pattern was compared to patterns previously reported for humans, cats, and rats. Finally, the tendency for some measures to fall below their baseline levels after an initial rebound was discussed in terms of "sleep inhibition" and servomechanism theory.

Respiratory Adaptations in Sleep

Abstract: The current era of research into the physiology of sleep began in 1953 when Aserinsky and Kleitman (2) first described REMl sleep and its association with a characteristic EEG pattern, dreaming, and changes in autonomic nervous system activity including respiration. This important discovery demonstrated conclusively that the traditional view of sleep as a homoge­ neous state was incorrect, and indicated that preexisting observations or theories regarding sleep had to be reexamined or reinterpreted taking the stage of sleep into consideration. Accordingly much of the research in sleep physiology during the past twenty years has been directed towards a defini­ tion of the physiological differences between REM and NREM sleep and towards elucidation of the specific mechanisms and purposes that underlie the different sleep stages. In recent years these same goals have been applied increasingly to the study of respiration during sleep. To the extent that the fundamental purposes and mechanisms of sleep itself remain uncertain, so too are the purposes and mechanisms of the respiratory adaptations to sleep. Nevertheless the changes in respiration that occur in the different stages of sleep have now been studied extensively, at least in purely descrip­ tive terms. In addition, attempts have been made, although fewer in num-

Nocturnal sleep in separated monkey infants.

Abstract: • Nocturnal sleep was recorded from ten unrestrained, groupliving Macaca nemestrina (pigtail) monkey infants, using implantable multichannel biotelemetry systems, during the agitation-depression behavioral reaction that follows maternal separation. Sleep disturbances during the four nights of separation were characterized by decreases in rapid eye movement (REM) time and in the number of REM periods, and increases in REM latency. Time awake and number of arousals were increased. Slow-wave sleep was not significantly affected. Sleep pattern changes were most pronounced the first separation night, and tended to decrease as separation continued, whereas behavioral measures of depression tended to increase as separation continued (up to four days). Sleep patterns returned to normal following reunion with the mother. Those infants who had the most severe sleep disturbances the first separation night (more time awake, less total sleep, less REM) also tended to become most depressed behaviorally later in the separation period.

Membrane potential of spinal motoneurons during natural sleep in cats.

Abstract: The membrane potential of spinal motoneurons was recorded during wakefulness, NREM sleep, and REM sleep in minimally restrained, behaving cats. At the onset of sleep, the membrane potential generally increased in polarization in rough proportion to time spent asleep. During the postural atonia of REM sleep, the membrane potential of all motoneurons was tonically hyperpolarized. Antecedents of NREM sleep electromyographic suppressions, and REM sleep myoclonic twitches were seen as transient hyperpolarizations and depolarizations, respectively.

Ethology of Sleep Studied with Time-Lapse Photography: Postural Immobility and Sleep-Cycle Phase in Humans

Abstract: Human sleep is characterized by episodes of immobility punctuated by major postural shifts The organization of this motor activity was shown with a combination of photographic and electroencephalographic recording to be periodic and related to the electroencephalographic sleep cycle The amount of immobility as measured photographically was positively related to subjective estimates of the goodness of sleep

Oxygen consumption and neonatal sleep states.

Abstract: 1. In thirty full-term infants in the first week of life, nursed in a constant volume, closed-circuit metabolism chamber in a neutral thermal environment (31·5-33·5 °C), measurements were made of oxygen consumption (˙VO2) during periods of rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. 2. The mean ˙VO2 during REM sleep was 5·97 ml. kg-1. min-1. In NREM sleep the mean ˙VO2 was 5·72 ml. kg-1. min-1. This difference was significant (paired t test P < 0·05). 3. When the direction of sleep state change was taken into account the difference in ˙VO2 between the two states was much less when REM sleep preceded NREM than when the change was in the opposite direction. In nineteen infants in whom the change was from REM to NREM the difference in ˙VO2 (6·18 and 6·03 ml. kg-1. min-1) was not significant (P > 0·05). The mean difference when the sleep state change was from NREM to REM was significant (P < 0·01), the values being 5·54 and 5·81 ml. kg-1. min-1 respectively. 4. In the NREM state, a gradual diminution of ˙VO2 with time was consistently found. This was not the case in REM sleep. 5. In twelve infants studied in a cool environment (29 ± 0·5 °C) ˙VO2 during REM sleep was 7·77, and during NREM sleep it was 6·58 ml. kg-1. min-1, (P < 0·001). Thus even the maximum difference found in a neutral thermal environment of 6·6% was significantly increased to 14·9% (P < 0·01) with mild thermal stress. 6. No consistent changes in ˙VO2 with time were found in either REM or NREM sleep in twelve infants studied in a cool environment, in contrast to the findings in thermal neutrality

Physostigmine alters onset but not duration of REM sleep in man.

Abstract: Physostigmine (1.0 mg) or placebo were administered intravenously over 1-h period to seven male normal volunteers beginning 35 min after sleep onset. The results indicate that physostigmine induced the onset of REM sleep but did not significantly alter the duration of individual REM sleep periods. Physostigmine significantly shortened the REM latency and the duration of the second non REM period. After inducing the onset of the first REM period(s), physostigmine also appeared to advance succeeding REM-nonREM sleep cycles relative to sleep onset even when the duration of each cycle was unaffected.

Home-Recorded Sleep in 2− and 9-Month-Old Infants

Abstract: Home recorded videotapes of all-night sleep were obtained for 32 2-month-old and 38 9-month-old infants. Changes in the proportionate amounts of time spent in active sleep, quiet sleep, wakefulness, and out of the crib were significantly related to age. Sleep-cycle lengths did not change with age, but the state relationships within sleep cycles showed maturational effects. Temporal patterning of sleep states was present by 9 months. Time-lapse video recording of sleep provides an opportunity for nonobtrusive monitoring of sleep longitudinally in normal and pathological infants.

The effect of physostigmine on normal human sleep and dreaming.

Abstract: • Physostigmine, an anticholinesterase that increases the action of brain acetylcholine, induces rapid eye movement (REM) sleep in normal humans. In this study we show that man dreams during physostigmine-induced REM sleep. Seventeen normal volunteers were pretreated with methscopolamine and received one intravenous infusion per night of either placebo or physostigmine either ten or 35 minutes after sleep onset. Subjects were awakened at specific times after infusion and interviewed regarding any sleep mentation prior to awakening. Results indicated that dreaming occurred during physostigmine-induced REM periods but that physostigmine did not alter mentation during non-REM sleep. These dreams were similar to spontaneous REM sleep dreams in content, vividness, unusualness, and emotionality.

A psychophysiological investigation of the long-term effects of clozapine upon sleep patterns of normal young adults.

Abstract: A 25-night single-blind cross over design was employed to determine the long-term effects of clozapine on the sleep patterns of six normal young adults. Subjects received 12.50 mg placebo on the first and last five nights, whereas on the intermediate 15 nights 12.5 mg clozapine was administered. The subjects slept in the laboratory on the third and fourth nights to obtain baseline recordings, and on the eight, twelfth, sixteenth, and twentieth nights to determine the effects of clozapine on sleep variables. Recordings on nights 21 and 25 were used to assess withdrawal effects. Percentage stage 1 sleep and indices of body movements during sleep were significantly reduced, suggesting that clozapine may have sleep-inducing properties. There was no significant rebound of stage REM sleep during drug withdrawal despite a small but significant reduction in stage REM during drug administration. Numerous side effects, indicative of sleepiness, were reported on the mornings following drug administration, and there was evidence of a rapid tolerance to clozapine. These findings may limit the efficacy of clozapine as an hypnotic agent over an extended period of time. Further research on insomniac subjects is therefore indicated.

REM deprivation and divergent thinking.

Abstract: The contribution of REM sleep to divergent thinking was examined. Ten subjects were deprived of REM sleep and of equal length of NREM sleep. In both cases a divergent thinking task was assigned in the evening to be performed in the morning. The subjects' responses after NREM deprivation were numerically greater, included more positive reactions, and were more divergent and original than those produced after REM deprivation. The study thus reconfirms the hypothesis that REM sleep contributes to divergent thinking and supports the claim that it encourages the individual's adaptation to new situations.