Figure 1.
Group-averaged ERP voltage waveforms and scalp topography. a, Exemplar waveforms from parieto-occipital electrode sites (Pz, PO3, PO4, and Oz; see inset) are displayed for the “pair,” “sum,” and difference. Nonlinear neural response interactions start at ∼60 ms after stimulus onset. b, The ERP topography (back view shown) at 60 ms after stimulus onset in response to the “pair” and “sum” conditions is generally consistent with the C1 component, which is a posterior negativity (Foxe et al., 2008). The difference topography is positive over the posterior scalp, indicative of subadditive interactions. Plus, the topographic distribution differs between the “pair” and “sum” conditions (maxima/minima indicated by the cross).