Effects of voice harmonic complexity on ERP responses to pitch-shifted auditory feedback

ObjectiveThe present study investigated the neural mechanisms of voice pitch control for different levels of harmonic complexity in the auditory feedback.MethodsEvent-related potentials (ERPs) were recorded in response to +200 cents pitch perturbations in the auditory feedback of self-produced natural human vocalizations, complex and pure tone stimuli during active vocalization and passive listening conditions.ResultsDuring active vocal production, ERP amplitudes were largest in response to pitch shifts in the natural voice, moderately large for non-voice complex stimuli and smallest for the pure tones. However, during passive listening, neural responses were equally large for pitch shifts in voice and non-voice complex stimuli but still larger than that for pure tones.ConclusionsThese findings suggest that pitch change detection is facilitated for spectrally rich sounds such as natural human voice and non-voice complex stimuli compared with pure tones. Vocalization-induced increase in neural responses for voice feedback suggests that sensory processing of naturally-produced complex sounds such as human voice is enhanced by means of motor-driven mechanisms (e.g. efference copies) during vocal production.SignificanceThis enhancement may enable the audio-vocal system to more effectively detect and correct for vocal errors in the feedback of natural human vocalizations to maintain an intended vocal output for speaking.

► Auditory processing is enhanced for sounds with higher levels of acoustical complexity.
► Vocal production facilitates pitch error detection in naturally-produced human vocalizations.
► Human subjects control their voice pitch better for perturbations in voice auditory feedback compared with non-vocal complex or pure tone feedback.