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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 6 (1969), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: EEG recordings were made during waking (W) and the five sleep stages (REM, 1, 2, 3, and 4) on thirteen young adult males. For each stage, one-minute sections of the pa ietal EEG trace were digitized and subjected to Fourier analysis. The resulting spectral intensities were divided into five frequency bands; delta, theta, alpha, sigma, and beta.Linear discriminators for all six stages were calculated using stepwise multiple regression. The overall percent agreement with visual scoring was very poor, ranging from zero for stage 3 to 91% for stage 4. Linear discrimination between pairs of stages yielded slightly better results, but stages 1 and REM were indistinguishable.Delta is the best overall discriminator, increasing significantly through stages W, 1, 2, 3, and 4. Sigma is unique to sleep and is highest for stage 2. Theta is unimportant and beta plays no role at all.Spectral analysis of the parietal EEG lead is not sufficient to differentiate among the six states of consciousness studied here. The use of detectors for such phasic events as eye movement and K-complexes might aid sleep stage discrimination considerably.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 14 (1977), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: To determine: 1) the minimum amounts of sleep subjects would tolerate, 2) the changes in EEG sleep measures, and 3) whether subjects would revert to baseline sleep after study termination, 4 couples gradually reduced their sleep. Three couples reduced their TST in 30-min steps from a baseline of 8 hrs and one couple from a baseline of 6.5 hrs. Subjective estimates of sleep time, sleep quality, and mood were collected daily. Home EEG sleep recordings were obtained 3 nights a week.Two of the 8-hr sleepers reduced their sleep to 5.5 hrs, 2 to 5.0 hrs, and 2 reached 4.5 hrs. These 6 subjects continued sleeping 1 to 2.5 hrs below baseline amounts a year after reduction terminated. The 6.5-hr baseline couple reached 5.0 hrs and returned to 6.5 hrs TST during follow-up.Stages W, 2, and REM decreased significantly in absolute amounts. Percentage of stages W and 2 also decreased significantly. REM percent remained constant. Stage 3 was constant while stage 4 increased in both absolute and relative amounts. REM cycle length remained constant. Stage 4 rebound on 7-hr nights was not observed during times of greatest sleep reduction. Occurrences of stage REM within 10 min of stage 1 onset were observed in 2 subjects when their TST was below 6.5 hrs.Our results are consistent with other studies of shortened sleep, indicating that TST is the major determinant of sleep-stage characteristics.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 13 (1976), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: Young male Naval volunteers were denied normal noclurnal sleep and maintained on a 60-min lreatment-160-min testing schedule during 40 consecutive hrs. Ten subjects bicycled, 20 subjects controlled EEG activity during bedrest, and 10 subjects napped. Eight measures of addition, auditory vigilance, mood, and oral temperature were obtained. The Bedrest group showed significant impairment on all eight measures, and thus, gave no support to lite forced-rest theory of sleep function. The Exercise group was worse than the Nap and Bedrest groups for all measures. In spite of fragmented, reduced sleep (about 3.7 hrs per 24 hrs), the Nap group had no impairment on six of the measures. The results suggest that exercise increases the impairment due to sleep loss, and naps reduce or remove this impairment. Bedrest is not a substitute for sleep.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 12 (1975), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: The combined effects of total sleep loss and the deprivation of stage 4 or stage REM were studied in I two separate experiments. Two full nights or sleep loss preceded stage 4 deprivation or stage REM deprivation in Experiment 1 (N=12); 1 full night of sleep loss followed 3 nights or stage 4 deprivation or stage REM deprivation in Experiment 2 (N=I4).Total sleep loss before sleep stage deprivation significantly increased the number of attempts to enter stage 4, but had little influence on stage REM. A significant REM rebound was found in only one of the REM-deprived groups, but there was a significant stage 4 rebound in all groups on the first full recovery night, supporting the hypothesis from other studies that stage 4 has priority over REM in terms of recovery from sleep loss. The results suggested that stages 2, 3, and 4 partially overlap in their recuperative functions.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 12 (1975), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: EEG and autonomic habituation were studied during sleep stages 2 and REM. and during awake. Repeated presentations of the same stimulus to the same subjects within sleep stages and when awake permitted evaluation of habituation between tone sets within stag 2, REM, and awake, and from sleep to awake. Forty-six subjects were exposed to 800 Hz. 75 dB, 1- or 2-sec tones, presented in sets of 20 tones. During steep, there was no habituation of the EEC response. Habituation occurred for both FPR and HRR during stage 2, with no evidence of within-stage. between tone set habituation. No significant habituation occurred during REM for HRR or FPR. Evoked skin resistance responses were rare during both stage 2 and RKM. In the awake state, HRR was unresponsive but all other variables showed habituation. Tones presented during the night had no effect on the awake response.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 12 (1975), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: Can the deleterious effects of acute sleep loss on performance and mood be ameliorated by self-enhanced alpha activity? Fourteen Naval volunteers were divided equally into an experimental (alpha-contingent auditory feedback) group and a yoked control (pseudo feedback) group. All subjects received feedback plus performance and mood tests during 3 baseline days and following 2 days and 2 nights without sleep. Feedback was given for 45 min in the morning and 45 mm in the afternoon, preceding performance and mood tests. The self-enhanced alpha (experimental) subjects did produce more alpha than the yoked controls during all feedback sessions except for one pair that was discarded. Of eleven measures that were sensitive to deep loss, two performance scores and one mood score showed significantly less sleep-loss decrement for the self-enhanced alpha group (at the usual univariate. 05 level). Two recall scores and an anxiety score showed more impairment for the self-enhanced alpha group following sleep loss. The differences were not significant, however, by (he conservative Dunn-Bonferroni multivariate criterion, so our results are not conclusive.Alpha enhancement may help maintain performance that requires continuous attention, such us counting and auditory discrimination, but does not ameliorate the sleep-loss effect for anxiety, memory, and addition.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 11 (1974), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: Twelve young (17–21 yrs) male Navy recruits volunteered for a sleep loss study. After 4 baseline days, the Ss were completely deprived of sleep for 2 days and nights. Next followed an experimental phase of 2 days and nights after which all Ss received 2 nights of uninterrupted sleep.During the experimental phase, the 4 Ss in the REM-deprived group were aroused whenever they showed signs of REM sleep. The 4 Ss of the stage 4-deprived group were aroused whenever they showed signs of entering stage 4 sleep, and the 4 Ss of the Control group had uninterrupted sleep.All tests (speed and accuracy of addition, speed and accuracy of self-paced vigilance, errors of omission in experimenter paced vigilance, immediate recall of word lists, and mood) showed significant impairment after the first night of complete sleep loss. But during the experimental (sleep-stage-deprivation) and recovery phases, all three groups showed equal rates of recovery.Depriving the S of stage REM or stage 4 during recovery sleep does not affect the recuperation rate. Frequent arousals (50–100 per night) also do not impair recovery. The amount of sleep is probably more important than the kind of sleep.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 15 (1978), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: The length and rhythmicity of the REM cycle was studied using data from three laboratories. In the three studies, 25 subjects obtained their sleep in naps under three different sleep/wake schedules: 60/160 min (N =8), 30/60 min (N =10), and 60/120 min (N =7), over a period of 40 hrs to 10 days. Previous results from these subjects (Moses, Lubin, Johnson, & Naitoh, 1977) indicated that the REM cycle is sleep-dependent, rather than an expression of an ongoing Basic Rest-Activity Cycle (BRAC). As a further test of the sleep-dependent hypothesis, autocorrelation and r2 analysis was applied to the compressed sleep (i.e., all wake time between and within sleep periods subtracted) of the baseline, nap, and recovery conditions. Compared to baseline, there were no significant differences in nap REM cycle length in the 60/160 and 60/120 groups; the 30/60 group had significantly shorter cycles. It appeared that this REM cycle shortening was due to the significantly shorter REM episodes in this group. The nap r2 values were significantly lower than baseline in the 30/60 and 60/120 groups, indicating increased variability in the timing of REM episodes during naps. All the nap r2 values, however, were significantly larger than those obtained from a random distribution of sleep stages.To further examine the effects of the degree of sleep fragmentation on REM cycle rhythmicity, two additional groups of subjects whose sleep was fragmented by either REM or SWS deprivation were compared to the nap groups. REM deprivation was the most disruptive of REM cycle rhythmicity; the r2 values for REM deprivation were significantly less than those for napping or SWS deprivation.These data offer further support that the REM cycle is a sleep-dependent rhythm and is not an expression of an ongoing BRAC.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 13 (1976), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: Can performance and mood during sleep loss be maintained by self-induced high EEG alpha activity? In a previous study, most of the performance and mood measures showed sleep-loss impairment regardless of EEG alpha level, but attention and reported sleepiness were less impaired for the high-alpha group (although the differences were of doubtful significance). A constructive replication was carried out. In Group A (N=10) auditory feedback was contingent on high alpha, and in Group B (N=10) auditory feedback was contingent on low alpha and low theta. All subjects were repeatedly measured on auditory vigilance, addition, immediate recall, and feelings of sleepiness for 40 hrs during which no sleep was permitted. Sixty min of EEG feedback were given during each block of 220 min. Group A did produce significantly more alpha for the first 24 hrs but this difference was not maintained. Both groups had significant sleep-loss impairment on all measures. There were no significant differences between the groups in the amount of impairment. Self-enhanced EEG alpha activity does not prevent impairment of performance or mood during sleep loss.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 14 (1977), S. 0 
    ISSN: 1469-8986
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: The effects of exercise and sleep loss on recovery sleep were studied in young male naval volunteers. For 1 hr out of every 4 hrs during a 40-hr period, 20 subjects rested in bed and 10 subjects bicycled. Eleven measures of recovery night sleep were selected for comparison of the bedrest and exercise groups. Only one reached significance under the conservative Dunn-Bonferroni criterion: the exercise group had a higher percent total sleep time. The results indicate that exercise does increase the effects of sleep loss on recovery sleep, but that there is no simple, direct effect on specific sleep stages.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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