[The activation and suppression by light of human cerebral cortical activity].

EEG rhythm driving was studied in the dark, under action of constant illumination and after its switching off. The intensity of the background illumination influenced frequency-dependent brain reactivity changes. The results testify to the existence of the range of the optimal for brain activity illumination between the moderate (activating) and extra-high (suppressing) background light intensities. A conclusion is drawn on the possibility of application of electrophysiological techniques for revealing the optimal illumination conditions.