[Photoinduced resonance phenomena in the human electroencephalogram as a function of frequency, intensity, and duration of stimulation].

The features of resonance phenomena in high-resolution EEG structure were analyzed for two intensities and three values of duration of exposure to 20 constant frequencies of intermittent photic stimulation in a range of 1-20 Hz with 1 Hz steps. It was shown that with a 6 s step duration, an irregular activation of multiple spectral EEG components for both light intensities occurs. With longer durations (12 and 18 s) of fixed-frequency stimulation, the EEG reactions are of resonance nature. Low-intensity flashes cause only the resonance activation of the intrinsic oscillator in the range of dominant alpha-EEG frequency. During a more intensive stimulation, the resonance EEG phenomena are observed for the whole range of stimulation frequencies. The interval of 6-12 s is supposed to be the relaxation period for a system of brain electrical activity generation. After this time, the low-intensity stimuli cause the adaptation of the system to light, whereas more intensive flashes cause more pronounced resonance EEG phenomena and physiological effects.