Working memory facilitates the detection and correction of feedback errors in vocal pitch regulation

Abstract

In speech processing, information related to the speech motor command and sensory re-afference can be stored in working memory (WM) within a feedback circuit and recalled when needed to adjust the motor activity. Whether WM facilitates the online monitoring of speech motor control, however, remains unclear. The present event-related potential study sought to examine the impact of WM on the auditory-motor processing of pitch feedback errors. Participants sustained a vowel phonation while hearing their voice pitch-shifted + 200 or + 500 cents five times. In the WM task, participants were asked to determine whether the sequence of 5 pitch shifts was different or not between two consecutive vocalizations. In the control task, they did nothing but maintaining their vocalizations steady when exposed to pitch-shifted auditory feedback. The behavioral results revealed a significant increase of vocal responses in the WM task as compared to the control task. At the cortical level, the WM task elicited significantly larger N1 responses and smaller P2 responses than the control task. Taken together, these findings demonstrate the influence of WM on the neurobehavioral responses to pitch-shifted voice auditory feedback, indicating that WM can facilitate the detection and correction of pitch feedback errors in vocal motor control.