Binaural interaction in the human brain can be non-invasively accessed with long-latency event-related potentials

Invasive microelectrode measurements have demonstrated binaural interaction effects of summation, occlusion, and suppression. Here we demonstrate these phenomena in humans using non-invasive long-latency cortical event-related potential (ERP) components N1 and mismatch negativity (MMN). Subjects were presented with monaural and binaural stimulus trains consisting of frequent standard stimuli and deviant stimuli deviating from the standard either in frequency, intensity, or duration. The binaural N1 was smaller than the monaural N1, MMN for the intensity change was larger with binaural than monaural stimulation, whereas for the frequency and duration change, the MMN amplitude remained unchanged. Thus, cortical binaural interactions reflected suppression in the N1, summation for the intensity MMN, and occlusion for the frequency and duration MMNs.