Continuous EEG, stimulus onset, response and all other trigger codes were recorded at 200 samples/s with a gain of 10k within .01–30 Hz (−6dB/octave) using a 48-channel Grass Neurodata acquisition system and NeuroScan software (NeuroScan, 1993). A Lycra stretch electrode cap with tin electrodes was used for an expanded 10–20 scalp montage (Pivik et al., 1993; Jurcak et al., 2007) consisting of 10 midline (Nz, Fpz, AFz, Fz, FCz, Cz, Pz, POz, Oz, Iz) and 19 homologous pairs of scalp placements over each hemisphere (Fp1/2, AF7/8, F9/10, F7/8, F3/4, FT9/10, FC5/6, FC1/2, T7/8, C3/4, TP9/10, TP7/8, CP5/6, CP1/2, P9/10, P7/8, P3/4, PO7/8, O1/2). All electrode impedances were maintained at or below 5 kΩ. EEG was recorded with a nose tip reference, and the implicit nose reference channel was added to the montage offline. Cap placement was optimized by precise measurements of electrode locations with respect to landmarks of the 10–20 system (nasion, inion, auditory meatus, vertex).
