Fig. 4

Cortical event-related potentials (ERPs) following audiovisual stimuli recorded at Cz. ERPs to A, V, and AV stimuli in controls (a) and IRD (b) patients. In both groups, unimodal auditory responses elicit the largest N1/P2 deflections, with later responses for the visual N1. Across tokens, IRD patients show larger cortical responses than controls (e.g., compare N1 magnitudes). c Group comparisons of the audiovisual integration effect (difference wave) contrasting uni- and multimodal ERPs [i.e., AV – (A + V)]. Potentials different from zero indicate an enhancement in AV processing compared to the summed unimodal (A + V) responses. Bars below the traces show time segments where AV > (A + V) (i.e., significant multisensory processing, p < 0.05). Despite larger unimodal responses in IRD patients, only the controls show significant AV integration (~200 ms) after initiation of the audiovisual stimulus. Shading = ± 1 s.e.m