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.