The grand average ERP waveforms at midline sites for patients and controls to nontarget, target and novel stimuli are shown in Fig. 1. The waveforms show the expected component structure with early N1 and N2 potentials, most clearly evident for targets at the central site (Cz). The novelty P3 is also evident at this site and the target P3 is largest at the parietal site (Pz). The greater P3 to novels than targets at the Fz and Cz sites reflects the more frontocentral topography of the novelty P3.
