NEURAL CORRELATES OF SPEECH MOTOR CONTROL DURING ALTERED AUDITORY FEEDBACK

In speech communication, auditory feedback plays a crucial role in monitoring and adjusting speech to ensure accuracy and effectiveness. When speaking, the brain continuously compares the planned speech outcome with auditory feedback. If there is a mismatch between the intended auditory target and the actual perceived speech output, the brain initiates corrective adjustments to minimise errors. One effective method to investigate speech motor control is using altered auditory feedback tasks. In these tasks, participants are exposed to real-time perturbations in pitch, loudness, or formant frequencies. Participants generally respond by adjusting their speech in response to feedback perturbation. In the current MRI study, we investigated the brain areas involved in speech motor control during altered auditory feedback. We scanned 48 native Mandarin Chinese speakers while they read the syllable “dē” out loud. Speech was recorded and fed back to them either normally or with an increase in the first formant frequency. Speech production and feedback occurred during a short silent interval between echo-planar volumes. As participants adapted to the altered feedback by reducing the frequency, activity increased in the left posterior cerebellum and decreased in sensorimotor cortex. These changes are thought to reflect the role of the cerebellum in forward modelling and the establishment of refined feedforward motor commands in the sensorimotor cortex. Resting-state data obtained before and after the task, revealed that the adapted state was characterised by strengthened functional connectivity within the superior temporal cortex bilaterally and dorsomedial sensorimotor cortex, consistent with consolidation of a new sensorimotor mapping.