Effects of exercise on the coherence of human EEG signals at selected hemispheric sites

This study investigated the effects of exercise on the intrahemispheric coherence of human electroencephalographic (EEG) signals. The frontal and temporal sites of each hemisphere (left: F3, T3; right: F4, T4) were selected as the sites to be compared. The subjects were divided into an exercise group and a control (nonexercise) group. Subjects rested for ten minutes; exercised on a cycle ergometer or watched a videotape for three consecutive five-minute periods, and then rested again for ten minutes. EEG recordings were taken during each of these five activity periods. The coherences between F3 and T3 and between F4 and T4 were calculated for each activity period. The coherence values were averaged across a specific frequency band (alpha, beta 1, or beta 2), and a randomized block-design test was applied to the z-transformed mean coherence values to determine whether any significant differences existed among the coherences within a particular frequency band. In the exercise group the right- and left-hemisphere alpha-band coherences for all three exercise periods were significantly decreased compared with the alpha-band coherence for the final rest period. In the control group the right-hemisphere beta 1-band coherences for the videotape periods were significantly decreased compared with the beta 1-band coherence for the initial rest period.