Coherence was calculated within BrainVision Analyzer using the following equation: Coh(c1,c2)(f)=∣CS(c1,c2)(f)∣2/(∣CS(c1,c1)(f)∣∣CS(c2,c2)(f)∣), where CS(c1, c2)(f) = Σ c1, i (f) c2, i (f). For the same frequency bands as above, coherence values were computed from the cross spectrum of selected electrode pairs. Specifically, intrahemipsheric coherence was examined through electrode pairs F3-C3, F3-P3, F3-T7, C3-P3, C3-T7, P3-T7 on the left hemisphere, and F4-C4, F4-P4, F4-T8, C4-P4, C4-T8, P4-T8 on the right hemisphere. In addition, inter-hemispheric coherence was calculated between electrode pairs F3-F4, C3-C4, P3-P4, and T7-T8. All EEG coherence variables were transformed using an arcsin transform (Jelic et al. 2000) to better approximate a normal distribution.
