Liu, H., Meshman, M., Behroozmand, R. and Larson, C.R.
Differential effects of perturbation direction and magnitude on the neural processing of voice pitch feedback
Clinical Neurophysiology,  122, 951-957, 2011, PMCID: PMC3151676

Abstract

Objective
The present study examined the neural representations of voice pitch feedback perturbations during vocalization.

Methods
N1-P2 complex event-related potentials (ERPs) were recorded from twelve right-handed speakers when they sustained a vowel phonation and their voice pitch feedback was randomly shifted ±100, ±200, and ± 500 cents with 200 ms duration.

Results
The results showed that larger pitch-shifted stimuli led to greater N1-P2 peak-to-peak magnitudes when voice pitch feedback was shifted downward. Downward stimuli generated larger auditory ERP amplitudes than upward stimuli for 200 cents and 500 cents pitch-shifted stimuli. Shorter N1 and P2 latencies were associated with larger magnitudes of pitch feedback perturbations.

Conclusion
N1-P2 complex ERPs can be used to reflect the neural processing of voice pitch feedback perturbations during vocalization as reflected by their sensitivity to the magnitude and direction of pitch-shifted stimuli.

Significance
The findings of the effects of the interaction between stimulus magnitude and stimulus direction on the N1-P2 complex suggest that neural representations of pitch feedback perturbations may be highly depended on the stimulus features.