Behroozmand, R., Karvelis, L., Liu, H. and Larson, C. R.
Vocalization-induced enhancement of the auditory cortex responsiveness during voice F0 feedback perturbation
Clinical Neurophysiology, Volume 120, Issue 7, July 2009, Pages 1303-1312

Auditory neural responses to self-produced sounds have been shown to be suppressed during active vocalization compared to passive listening to the playback. A recent study in primates showed that the vocalization-induced suppression of auditory neurons enhances their sensitivity to feedback perturbation suggesting that the co-occurrence of vocalization and feedback perturbation onsets can elicit neural responses that reflect the simultaneous effect of two phenomena: 1) suppression due to vocalization and 2) suppression-induced enhancement of the neural responsiveness during feedback perturbation. We tested the hypothesis that self-vocalization enhances auditory responsiveness to voice pitch feedback perturbation by temporal separation of a pitch-shifted stimulus (PSS) and vocalization onset on neural responses to feedback perturbation.  We also investigated the effect of voice pitch-shifted feedback magnitude on neural responsiveness. Event related potentials (ERPs) were recorded in 15 subjects in response to +100, +200 and +500 cents pitch-shifted voice feedback during active vocalization and passive listening to the playback signal. Results revealed significantly larger P1 and P2 ERP components during vocalization than passive listening. The vocalization-induced increase in neural responsiveness was significantly larger for +100 than +500 cents pitch-shifted feedback suggesting that although auditory cortex is more responsive to voice F0 feedback perturbation during vocalization, the vocalization-induced enhancement of the neural responsiveness is greater during smaller compared with larger voice F0 feedback deviations.