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 that early, left-lateralized inferior parietal ERP negativities (N1, N2) to visual stimuli observed with a nose reference are due to a volume-conducted fusion of two or more (cf. inferior parietal sinks associated with visual P2 source) partly-overlapping potentials of different cortical origin. In fact, a linked-mastoids reference will likely project an N2 towards the mid-frontocentral region, a location conveniently fitting dipole models suggesting an underlying ACC source (van Veen and Carter, 2002). More importantly, almost the same cortical region was implicated in both neuronal generator patterns underlying the visual and auditory N2 sink, which may suggest reduced, modality-independent ACC contribution to this frontocentral component in schizophrenia. This is also entirely consistent with recent combined fMRI and ERP evidence in healthy adults during auditory and visual oddball tasks, showing for both modalities similar overall ACC activation, the main contributor of N2b, but modality-specific connectivity to primary auditory (Heschl’s gyrus) and visual (striate) cortices (Crottaz-Herbette and Menon, 2006). These findings suggest top-down
