Propagation of Alpha Waves Corresponding to Subjective Preference from the Right Hemisphere to the Left with Changes in the IACC of a Sound Field
Shin-ichi Sato, Kazuki Nishio, and Yoichi Ando

Attempts are made to clarify the relationship between the person's brain activity and a subjective evaluation of the sound field. For this purpose, we analyzed the autocorrelation function (ACF) of the alpha wave in the electroencephalogram (EEG) measured on the scalp over cerebral hemispheres. The cross-correlation function (CCF) was analyzed to investigate the flow of alpha waves on the scalp over both the left and right hemispheres. To describe the temporal characteristics of the alpha waves, when the magnitude of interaural cross-correlation function (IACC) of a musical stimulus changed, the effective duration of the envelope of the ACF (t_e) was analyzed. The values of t_e were found to closely correspond to the subjective preference only in the right hemisphere (electrode T4). For the characteristics of the signal flow on the scalp, the maximum value of the CCF (|f(t)|_max) between the alpha waves measured at different electrodes and its delay time (t_m) were analyzed. The right hemisphere (T4) was found to be activated first, and this activity propagated toward the left hemisphere (T3). The propagation time from T4 to T3 was about 100 ms.

Key words: electroencephalography (EEG), alpha wave, subjective preference, IACC, autocorrelation function, cross-correlation function