2010
Volume 10, Number 3, p.p. 91–95
Asymmetry between alpha wave and NK cell changes during forehead light exposure
Tsutomu Kamei,1,2,* Yoshitaka Toriumi,3 Seiji Yamaguchi,3 Hiroaki Kumano4 and Seiichi Jimbo5
1 Institute for Transcultural Health Studies, European University Viadrina, Frankfurt (Oder), Germany
2 Department of Medical Research, Shimane Institute of Health Science, Izumo, Japan
3 Department of Pediatrics, Shimane University Faculty of Medicine, Izumo, Japan
4 Department of Stress Sciences and Psychosomatic Medicine, Graduate School of Medicine, University of Tokyo, Japan
5 Mitsubishi Kagaku Bio-Clinical Laboratories, Inc., Tokyo, Japan
We exposed the forehead of human subjects to red light from a light-emitting diode while ensuring the eyes of the subjects were shielded. Natural killer (NK) cell activity and the number of peripheral NK cells (CD57–CD16+) were examined. The relationship between changes in these immunological parameters and the change in brain alpha waves was investigated. Upon exposure to the light, a tendency toward increased NK activity was observed, along with a significant increase in the level of CD57–CD16+. Correlation was observed between the change in level of CD57–CD16+ and the change in effective amplitude of alpha waves in the first 5 min of exposure. The most significant correlation was in the frontal region. Moreover, the correlation was more significant in the right cerebral hemisphere than in the left. These results suggest that frontal exposure to red light induced a change in alpha wave amplitude that was greater in the right hemisphere than in the left hemisphere, and which was positively correlated with changes in peripheral NK cells.
Keywords: alpha wave, asymmetry, forehead, NK cell, photodiode