EEG signal was measured at Fz and Cz sites simultaneously with the MEG signal in order to provide a complementary measure of the effects of alcohol on event-related theta power and to relate our findings to previous EEG studies. The signal was referred to an electrode placed on the tip of the nose, whereas the right earlobe served as ground. An electrooculogram (EOG) was recorded as well, with bipolarly referred electrodes placed at the outer canthus of the left eye and just above the nasion. Electrode impedance did not exceed 5 kΩ. Good quality complete EEG data sets were acquired from 20 participants and analyzed with the same signal-space analysis described above. Grand averages of event-related power were expressed as relative change to the prestimulus period and were calculated as follows: normalized power N(t,f ) = [P(t,f ) – B(f )]/B(f ), where P(t,f ) is raw total power at timepoint t and frequency f and B(f ) is mean power for frequency f in the prestimulus time window. The total event-related theta power was averaged across the 450–650 ms latency window and analyzed with repeated measures ANOVA as described above.
