Single trial EEG epochs were stimulus-locked to the onset of each tone, including data from 250 ms before the tone onset and 750 ms after its onset. Individual trials were baseline corrected using the 100 ms period preceding the tone onset after correcting for eye movements and blinks using EOG data (Gratton et al., 1983). Finally, trials containing artifacts (voltages exceeding ±100 μV) in any of the central 9 electrodes (F3, Fz, F4, C3, Cz, C4, P3, Pz, or P4) were rejected.
