Differential effects of perturbation direction and magnitude on the neural processing of voice pitch feedback

Objective: The present study examined the differential effects of voice auditory feedback perturbation direction and magnitude on voice fundamental frequency (F₀) responses and event-related potentials (ERPs) from EEG electrodes on the scalp. Methods: The voice F₀ responses and N1 and P2 components of ERPs were examined from 12 right-handed speakers when they sustained a vowel phonation and their mid-utterance voice pitch feedback was shifted ±100, ±200, and ±500cents with 200ms duration. Results: Downward voice pitch feedback perturbations led to larger voice F₀ responses than upward perturbations. The amplitudes of N1 and P2 components were larger for downward compared with upward pitch-shifts for 200 and 500cents stimulus magnitudes. Shorter N1 and P2 latencies were also associated with larger magnitudes of pitch feedback perturbations. Conclusions: Corresponding changes in vocal and neural responses to upward and downward voice pitch feedback perturbations suggest that the N1 and P2 components of ERPs reflect neural concomitants of the vocal responses. Significance: The findings of interactive effects between the magnitude and direction of voice feedback pitch perturbation on N1 and P2 ERP components indicate that the neural mechanisms underlying error detection and correction in voice pitch auditory feedback are differentially sensitive to both the magnitude and direction of pitch perturbations.