Neurobiology of Sleep-Wakefulness Cycle 2(2): 45-55, 2002
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© 2002 NSWC
Accepted in revised form 23 June 2002; recieved 4 April 2002.
As a result of a more or less detailed description of the baseline sleep-wakefulness cycle (SWC) in man some comments have been made about SWC classification commonly accepted at present. They concern particularly the recognition of the alpha rhythm, developing in human subjects ready to fall asleep after closing the eyes, as a correlate of the phase of wakefulness. From the neurobiological position, this state is considered to be the beginning of a consummatory phase of sleep as an instinctive behavior. However, not denying the convenience of the conventional classification for the clinical purposes, from the neurobiological point of view it is more acceptable to divide the orthodoxical sleep in man and other mammalian species into two stages, i.e., light slow wave sleep (LSWS) and deep slow wave sleep (DSWS).
Furthermore, was studied the effect of partial deprivation of the paradoxical phase of sleep (PSD) on the deprivation and postdeprivation structure of human nocturnal sleep cycle. Partial PSD was made by the way of mere awakening of the subject 5-6 min after the onset of paradoxical sleep (PS) and subsequently has been maintained by active wakefulness for 10-15 minutes during which the subject was required to retell the content of the dreams seen before awakening. To determine the different phases and stages of the SWC the electroencephalogram (EEG) from the frontal, parietal and occipital areas of the neocortex, activity of oculomotor muscles, mental and submental muscles and cardiac rhythm were recorded on a multi-channel polygraph of the firm "San'ei". Analysis of the data obtained shows:1) the lack of accumulation of the need for PS and respective increase of the PS onset frequency during PSD, 2) lack of PS rebound in the following postdeprivation night, 3) an increase in the amount of DSWS during deprivation night, 4) development of the phenomenon of self-arousal from PS on the basis of lucid dreaming and purpose to retell its content, 5) lack of significant changes of the overall structure of nocturnal sleep in postdeprivation period. Analysis of these data relied on the knowledge of neurobiological and neuropsychological mechanisms of the SWC in general.
Key Words: Partial PSD; SWS rebound; SWC during and after PSD; Lucid dreaming; Self-arousal phenomenon.
Correspondence: Oniani Tengiz, Prof.,
Department of Neurobiology of Sleep-Wakefulness Cycle,
I.S. Beritashvili Institute of Physiology, Georgian Academy of Sciences,
14, L. Gotua str., Tbilisi, 380060, Georgia.