All seven collaborating sites used identical experimental procedures and EEG acquisition hardware and software programs. EEG was recorded using a fitted electrode cap (Electro-Cap International, Inc., Eaton, OH) with a nose reference point and a forehead ground electrode. Continuous EEG was sampled as the subjects performed the standard visual oddball paradigm that was selected to elicit the event-related potential containing the P300 component [Porjesz et al., 1998]. The task involves the presentation of three types of visual stimuli: 12.5% are target (X), 75% are non-target (squares) and 12.5% are novel (non-repeating colored polygons). Subjects responded to the appearance of target stimuli by pressing a button with either the left or right index finger. The artifact control and data reduction procedures have been described in great detail in two earlier papers on theta and delta EROs [Jones et al., 2006b; Rangaswamy et al., 2007].
