Abstract
It has been suggested that speech production is accomplished by an internal forward model, reducing processing activity directed to self-produced speech in the auditory cortex. The current study uses an established N1-suppression paradigm comparing self- and externally-initiated natural speech sounds to answer two questions: (1) Are forward predictions generated to process complex sounds, such as vowels, initiated via a button press? (2) Are prediction errors regarding self-initiated deviant vowels reflected in the corresponding ERP components? Results confirm an N1-suppression in response to self-initiated complex sounds. Furthermore, these predictions are specific as the N1-suppression is modified in response to deviant vowels. In addition, self-initiated deviant vowels elicit an enhanced N2b and P3a compared to externally-produced deviants, confirming prediction specificity. Results show that prediction errors are more salient in self-initiated auditory stimuli of higher complexity compared to sinusoidial sounds, crucial for more efficient error correction during speech production.