3.2 ERP data
ERP activity initiated about 2000 ms before stimulus onset. Negative slow ramps were present in different scalp areas with different slopes and shapes, which were maximal at stimulus onset (Figure 3). This wide negativity was present in medial prefrontal (the pN), central (the BP), parietal (the pBP), and occipital areas (the vN) as shown by scalp topography (Figure 4). The pN was clearly visible in the Keypresscondition only.