[Peculiarities of interhemisphere interaction at different levels of consciousness]

Transition from wakefulness to drowsiness was used as a model of a gradual decrease in the consciousness level. Subjects' self-reported changes in the contents of consciousness, namely: the intensity and quality of involuntary mental processes, served as an indicator of the consciousness level. Each observed level of consciousness was shown to be characterised by a certain EEG profile. It was also shown that the state in which the subject signals of a slowdown of the "internal speech" or the "lapse of thoughts" corresponds to the lowest level of activation. In this case, the interhemisphere connections involving the main mechanism of cognitive information transmission, i.e. the EEG high-frequency rhythms, becomes suppressed.