[Effect of rhythmic photic interference on the working electroencephalogram and efficiency of human movements]

The effect of rhythmic light flashes on the space-time pattern of brain biopotentials during motor functions and biomechanical efficiency of man's actions was investigated. As the motor model we used the ability to maintain equilibrium when standing on the toes of one foot. Electroencephalography (EEG) from 12 neocortical areas and oscillations of the body mass center (stabilography) were recorded in 20 men who performed the exercise under normal conditions and during light flashes of 12 Hz. The resultant EEG and stabilograms were exposed to correlations-spectral and coherent analysis with the aid of an EC-1035 computer. Light flashes induced a change in the EEG peaks and flicker fusion frequency, a significant increase (by 23-108%, P less than 0.05) of the density of biopotentials corresponding to the light stimulation frequency, and a redistribution of the number of high intercentral correlations between neocortical motor centers. When the light flashes were presented, 75-85% test subjects showed a 0.19-0.26 increase in the biopotential coherence of the premotor, motor and sensomotor areas. They also exhibited a significant decrease in the body stability (P less than 0.01) and an increase in the stabilographic amplitude and frequency (P less than 0.01). It is suggested that the decline of biomechanical efficiency is associated with the disorders of the space-time integration between neocortical centers involved in the motor control system that are responsible for the execution of motor acts.