Interaural phase and level effects on binaural interaction component (BIC) of the brain‐stem auditory evoked potential

Abstract

Electrophysiological studies have elegantly demonstrated that neurons in lower brain‐stem nuclei are exquisitely sensitive to the parameters of sound that mediate localization and lateralization phenomena. In the present study, the binaural interaction component (BIC), derived from brain‐stem auditory evoked potentials, was obtained using low‐frequency stimuli with various combinations of time and level differences delivered through earphones. The aim has been to determine whether these volume‐conducted multineuronal responses reveal any of the neural mechanisms of lateralization. The findings show that characteristics of the binaural interaction component, e.g., latency, amplitude, and waveform morphology, evoked by low‐frequency tone bursts, are differentially altered with changes in interaural phase. The effects on the binaural interaction component with interaural level differences were also substantial but not similar to the changes produced with phase. From this research, it has become apparent that, given appropriate recording and stimulating parameters, many nuances of binaural hearing may be neurophysiologically addressed in studies of volume‐conducted evoked and derived potentials.