source (cf. locations 38 and 88, approximately CCP3h and CCP4h; Fig. 13C, column 1 and 4; Fig. 13D, column 4) during the later, response-related interval. This stimulus-locked mid-frontal sink and centroparietal source pattern is entirely different from a P3b source topography (cf. Fig. 11D, right column), but highly similar to the response-locked ERN-like CSD topography. This mid-frontal, response-related negativity (FRN) can be reliably observed in stimulus-locked CSD waveforms during different cognitive paradigms and study populations employing less-dense EEG montages (Kayser and Tenke, 2006a, 2006b; Kayser et al., 2007, 2009, 2014; Tenke et al., 2008, 2010); however, it remains largely hidden in stimulus-locked ERPs.
