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

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...