Cross-modal auditory adaptation on visual perception revealed by ERPs. Grand-averaged ERPs in response to happy test faces (upper panel) and sad test faces (lower panel) preceded by the Tone Adaptor and Laughter Adaptor. ERP waveforms showed robust P1-N170-N2-Plate complex in the left hemisphere (average of electrodes P1, P3, P5, P7, PO3, PO5, PO7, O1, and CB1) and right hemisphere (average of electrodes P2, P4, P6, P8, PO4, PO6, PO8, O2, and CB2).