After averaging EEG data with respect to rare events, we observed an ERP waveform in the 300–400 ms range, mostly distributed over the centro-parietal region, and largely corresponding to the P300 component (Figure 3). Conversely, it was more complicated to distinguish the P2 component, more frontal and early (at around 250 ms) with respect to the P3 component. In addition, we also detected the visual N1 component at the latency of about 85 ms. Nonetheless, the direct source localization of the ERP response to rare events seemed not to adequately show the different sources activated by task execution (Figure 3). Particularly, localization at 85 ms did not include primary visual areas in the occipital regions, but mainly parietal and temporal areas.
