Phase synchronization in human EEG during audio-visual stimulation

Synchrony of EEG data recorded under influence of audio-visual stimulation was investigated. Instantaneous phases were derived from Wavelet transform method. Phase synchronization is assessed quantitatively via measure derived from uniformity of phase difference distribution. EEG data came from 6 healthy volunteers repeatedly exposed to 20 min AVS program with intervals with stable stimulation at 4 and 17 Hz. Phase synchronization during AVS significantly increased in comparison to non stimulation conditions in all examined cortex locations. The lowest increases in synchronization occurred in the frontal areas. In central region no dumping in synchronization was recognizable in comparison to backward locations where visual processing centers are situated.