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AN ELECTROGRAPHIC STUDY ON THE MODIFICATION OF THE SLEEP CYCLE PATTERN BY REPEATED AROUSAL STIMULATION IN BOTH MAN AND CATS (THE STUDY ON SLEEP, III)
Author(s) -
Okuma Teruo,
Fujimori Masamoto,
Hayashi Akio
Publication year - 1964
Publication title -
psychiatry and clinical neurosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.609
H-Index - 74
eISSN - 1440-1819
pISSN - 1323-1316
DOI - 10.1111/j.1440-1819.1964.tb00013.x
Subject(s) - sleep (system call) , arousal , stimulation , psychology , sleep patterns , cats , sleep onset , electroencephalography , sleep induction , rhythm , audiology , anesthesia , insomnia , neuroscience , medicine , psychiatry , melatonin , computer science , operating system
S ummary (1) The modifiability of the sleep pattern by repeated arousal stimulation was investigated on cats and human subjects through electrographic and behavioral observations. (2) Two kinds of sleep rhythms fast and slow, were observed in cats and men. The faster was the sleep cycle which had been defined as a period between the two successive activated sleep stages. The slower one may be called the sleep phase which is an assembly of several sleep cycles and recurs several times a day in the cat (polyphasic type of sleep) and once in the human adult (monophasic types of sleep). (3) The sleep cycle pattern of the cat was found to be profoundly modified by the repeated arousal stimulation. When a period of activated sleep was interrupted by relatively weak arousal stimulation, the next period of activated sleep recurred much sooner than expected and number of brief sleep cycles could be established successively. The pattern of the sleep phase of the cat, on the other hand, was not influenced significantly, though the sleep cycle pattern in each sleep phase might be modified considerably. (4) A similar principle was also applicable to the modifiability of the sleep pattern of the human subject, but the sleep cycle pattern of the man during a night sleep tended to be more stable and less modifiable than that of the cat. (5) When the activated sleep of the human subject was interrupted by a relatively weak arousal stimulation, the EEG pattern showed a direct shift from arousal or drowsy pattern to the activated sleep pattern without passing through spindle and slow activity stages. The electrocortical pattern of the cat in such instances however, showed a gradual shift from arousal, through spindle and slow activity stages, to the activated sleep stage even though they were very brief. The differences between cats and man in the neocortical electrographic pattern and also in the response to the arousal stimulation during the activated sleep will be explained by the difference in the development of the cerebral cortex between the two species. (6) The modifiability of the sleep cycle and sleep phase patterns by repeated arousal stimulation indicates that a sustained inhibitory process may exist in the background of the natural sleep, particularly during the period of the activated sleep.