In contrast to N1, robust reductions of N2 sink amplitudes were found for patients across modalities (cf. Alain et al., 2001 cf. Alain et al., 2002a). Interestingly, the presence of a left-lateralized auditory N2 sink at medial central sites in controls but not patients parallels the visual N1 sink findings, which may also hint at a failure of automatically accessing phonological/semantical word representations in the left hemisphere (cf. Price et al., 2003). ERP studies reporting robust N2 reductions in schizophrenia have often used a nose reference (e.g., Bruder et al., 1998, 1999; Kayser et al., 1999, 2001) or target-minus-standard difference waveforms (e.g., O’Donnell et al., 1993; Umbricht et al., 2006), whereas a linked-mastoids or ear lobe reference tends to lessen its noticeability. While temporal characteristics of the visual N2 sink and its group difference in the current study were in close agreement with our previous findings (Kayser et al., 1999), the reference-free CSD transform revealed maximum current flow at vertex and not over the left inferior parietal region, as presumed when interpreting our nose-referenced ERP data. Therefore, we must conclude
