[About a possible role of parasomnia as a factor of stabilization of sleep cycles].

Cyclical organization of sleep is one of necessary conditions of normal human and animal life activity and one of basic manifestations of the circadian cycle. Transition from the slow-wave to the paradoxical sleep is often accompanied by brief, sometimes rhythmical motor and autonomic reactions that do not cause arousal, but seem to promote activation of the mechanisms providing the "shift" of the sleep phases. Immaturity (or damage) of the neurophysiological mechanisms responsible for the "shift" of the sleep stages leads to hindering of alternation of the sleep phases, which disturbs their normal sequence and leads to deficit of reparative and homeostatic processes; this is manifested in deterioration of the neuropsychical state during wakefulness. The data are presented which allow suggesting that as a compensatory mechanism promoting the sleep phase shift there can appear stereotypical motor or autonomic reactions - pathological parasomnia, for instance, enuresis. Episodes of the pathological parasomnia promote normalization of the sleep stage alternation and thereby affect positively recovery of its cyclical organization.