Hemisphere lateralization underlying auditory feedback control of voice F0.

Abstract

Reflexive compensation for unexpected pitch changes in auditory feedback for stabilization of voice fundamental frequency (F0) has been demonstrated using the frequency perturbation technique. However, neural mechanisms of the pitch‐shift reflex are still unclear. This study investigated hemisphere lateralization in the auditory processing of pitch changes by using event‐related potentials. During vocalization of sustained vowels, subject's voice pitch feedback was randomly shifted upward or downward 100, 200, or 500 cents with 200 ms duration. Simultaneously, brain activity was recorded through surface electrodes located on the scalp bilaterally referenced to linked earlobes. The results showed larger brain potentials (peak difference between P200 and N100) in the C3 (left) than in the C4 (right) site, indicating left hemisphere dominance in the central motor area, while right hemisphere dominance was found in the lateral frontal area with larger potentials in the F8 (right) than in the F7 (left) site. Furthermore, these patterns were maintained regardless of stimulus magnitude and stimulus direction. This preliminary study suggests that, although both left and right hemispheres are involved in voice production, functional lateralization of the brain may exist for voice F0 control. Results also suggest that lateralization varies along the anterior‐posterior dimension of the neural axis.