Noninvasive neurostimulation of left ventral motor cortex enhances sensorimotor adaptation in speech production

Brain Lang. 2020 Oct:209:104840. doi: 10.1016/j.bandl.2020.104840. Epub 2020 Jul 29.

Abstract

Sensorimotor adaptation-enduring changes to motor commands due to sensory feedback-allows speakers to match their articulations to intended speech acoustics. How the brain integrates auditory feedback to modify speech motor commands and what limits the degree of these modifications remain unknown. Here, we investigated the role of speech motor cortex in modifying stored speech motor plans. In a within-subjects design, participants underwent separate sessions of sham and anodal transcranial direct current stimulation (tDCS) over speech motor cortex while speaking and receiving altered auditory feedback of the first formant. Anodal tDCS increased the rate of sensorimotor adaptation for feedback perturbation. Computational modeling of our results using the Directions Into Velocities of Articulators (DIVA) framework of speech production suggested that tDCS primarily affected behavior by increasing the feedforward learning rate. This study demonstrates how focal noninvasive neurostimulation can enhance the integration of auditory feedback into speech motor plans.

Keywords: Auditory feedback control; Auditory feedback perturbation; Formant perturbation; Motor learning; Premotor cortex; Sensorimotor adaptation; Speech production; tDCS.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Feedback, Sensory / physiology*
  • Female
  • Humans
  • Learning / physiology*
  • Male
  • Motor Cortex / physiology*
  • Patient-Specific Modeling
  • Psychomotor Performance / physiology*
  • Speech / physiology*
  • Speech Acoustics
  • Transcranial Direct Current Stimulation*
  • Young Adult