Synchronization of Alpha-Band EEG Between Two Individual Persons During Autogenic Training and its Enhancement Through Biofeedback

• Published in: Applied psychophysiology and biofeedback 2011-09, Vol.36 (3), p.224
• Main Authors: Shiga, Kazumasa, Sakaguchi, Yutaka
• Format: Article
• Language: English
• Subjects: Analysis; Biofeedback training
• ISSN: 1090-0586

We measured EEG (brain wave) of two individual persons simultaneously during autogenic training (AT) and analyzed the relationship in their alpha-band (8-10 Hz) activities. EEG was measured at forehead and occipital of the subjects sitting on a chair with their eyes closed. Alpha-band activity at the occipital (i.e., occipital-alpha) was stably and commonly observed from all subjects, whilst the activity at the forehead (i.e., frontal-alpha) depended greatly on the subjects. To be more specific, stronger frontal activities were observed from more AT-experienced subjects. This might be because the frontal-alpha activity could be related to the magnitude of 'passive concentration' in AT. Note that frontal-alpha and occipital-alpha were anti-correlated to each other, implying that they were not independent. As for the relationship between the subjects, the correlation between frontal-alpha activities of two individuals gradually increased as the training session proceeded for some subject pais. This was more consistently observed when one of the subjects was an AT trainer and the other was an AT trainee, compared with the case that two subjects were both AT trainees. Although the underlying mechanism of this synchronization is unclear, it seems consistent with a view that AT could be more easily acquired when a person trains with experienced persons than when he/she trains solely. Aiming at inducing this enhancement effect effectively, we tried to give bio-feedback based on the correlation between frontal-alpha activities of two individuals. In concrete, the sounds were played when the peak frequencies of their frontal activities agreed with each other in the range of 10% and their correlation coefficient was greater than 0.6 within every 1 s interval. At the present, we have not obtained sufficient data showing significant effects of this feedback, but a preliminary result showed that the frontal activity of trainees tended to be enhanced with this bio-feedback, compared to the case of self-training. In addition, some subjects reported that they were encouraged by being informed that their brain activity became close to that of the experienced persons. We speculate that bio-feedback of the frontal-alpha correlation could promote the acquirement of AT. Keywords: -Synchronization -Alpha-band -Autogenic training