Abstract: Objective Electroencephalogram(EEG) is a modern examination method, which amplifies tiny bioelectrical signals of brain itself. This study focused on the differences of seven EEG spectral regional field powers: Delta(0.5~3.5 Hz), Theta(4~7 Hz), Alpha-1~(7.5~9.5 Hz), Alpha-2(10~12 Hz), Beta-1(13~23 Hz), Beta-2(24~34 Hz) and Gamma(35~45 Hz)) when the unilateral eye(right and left eye) is open and closed. Methods Fifteen healthy subjects(all were men; age: 19~27 years), in the resting state, in a quiet and comfortable room, who were asked to close and open unilateral eye(left-closed/open, right-closed/open) in counter-balanced order stimulation, while respective EEG was recorded and analyzed. Results In the resting state, regional EEG field powers of mid-frequency band Alpha-1 and Alpha-2 field powers were obviously higher in eyes-closed than in eyes-open state(Alpha-1, P=0.038; Alpha-2, P=0.02). Compared unilateral eye-closed and eye-open, there were no significant differences in alpha bands or other bands. Conclusion Alpha band power was significantly higher when subjects closed eyes than opened their eyes, however, when we compared unilateral eye-closed and eye-open differences of seven bands, significant differences was uncovered. We conclude that bilateral EEG powers are balanced via corpus callosum in persistent 2 min unilateral stimulation.

Key words: electroencephalogram, field power mapping, unilateral, eye-open, eye-closed