Figure 1 shows the comparison of grand average difference ERP waveforms and topographical maps for the NSAC and TNAD groups for the rare non-target and target conditions. The spatial distributions of the P3a and P3b were similar across groups, with the P3a component being fairly widespread with its maximum over the centro-parietal regions (CPz and Pz), and the P3b showing a more localized spatial distribution at the parietal electrode site (Pz). In accordance with the observed spatial distributions of the P3a and P3b subcomponents, the grand average difference ERP waveforms for the rare non-target and target conditions are displayed at CPz and Pz respectively.
