The purpose of this study was to test the hypothesis of the existence and independence of multiple generators of the sleep rhythms. Spatio-temporal analysis of the sleep EEG of 6 subjects was realised both visually and by multi-dimensional analysis of the parameters of spectral power (PS) and coherence (CH). Four results have been demonstrated: a relative decrease of the global CH during the transition from waking to deep sleep, with reappearance of high CH during paradoxical sleep (PS); (2) a negative correlation between the activities of frontal and occipital regions, mostly for alpha and theta frequencies; (3) a dominance of the activity of one hemisphere (the left here) during sleep, with a possible change of this dominance during paradoxical sleep; (4) a slow oscillation of power (SOP) with a periodicity of 1-5 min. variable according to subjects and sleep stages. These results suggest the existence of two partially independent groups of generators (anterior and posterior) for the slow frequencies of sleep.
