[Features of cortex areas system interactions in the left and right brain hemospheres during different human sleep stages].

The article is devoted to analysis of research brain biopotential field structure during different stages of natural night sleep in adults. The special attention is given to distinctions of the spatial organization of EEG interregional relations in the left and right hemispheres which are shown most strongly in the II and III sleep stages. The special role of frontal cortical areas in reorganization of brain system activity during falling asleep is highlighted. Essential strengthening of hemispherical interaction of cortex biopotentials fluctuations during falling asleep--a stage of I(B)--along with its reduction in central and occipital cortical areas is shown during a slow wave sleep (II--IV stage) versus wakefulness.