Neural correlates of sensory change in speech motor learning

Takayuki Ito (1, 2) , Joshua H Coppola (2, 1) , David J Ostry (2, 3)

1 GIPSA-PCMD - GIPSA - Perception, Contrôle, Multimodalité et Dynamiques de la parole
2 Haskins Laboratories
3 McGill University = Université McGill [Montréal, Canada]

Speech motor learning changes speech perceptual processing as well as motor function. However, the neural mechanisms underlying the sensory plasticity associated with speech motor learning are little understood. Given the presence of behavioral changes, one expects that comparable changes to speech- related auditory and somatosensory cortical processes may possibly be detected using brain imaging techniques. We here examined whether auditory and somatosensory event-related potentials are altered in conjunction with speech motor adaptation. We tested native speakers of American English using an adaptation to altered auditory feedback (AAF) training task. As subjects repeated aloud the speech utterance “head,” the produced sound was fedback through headphones while the first formant frequency of /ea/ was decreased gradually over 50 repetitions and held at a maximum change for 110 repetitions. In order to evaluate the effects of the resulting adaptation on cortical sensory processes, we recorded auditory and somatosensory event-related potentials (ERPs) using 64-channel electroencephalography before and after the AAF training. Auditory ERPs were elicited by using the synthesized vowel sound “e”. Somatosensory ERPs were elicited by facial skin deformation similar to that which occurs in conjunction with articulatory movements in the production of “head”. We found changes to auditory and somatosensory ERPs following AAF training in individuals who showed adaptation change to altered auditory feedback, but not in individuals who did not show an adaptation effect. Auditory ERPs in post training were significantly reduced at electrodes over the right frontal regions. In somatosensory ERPs, we found an enhancement of the sensorimotor cortical oscillation (mu rhythms) over left sensorimotor area in individuals who showed adaptation. These changes were correlated with the amount of adaptation in AAF training. This suggests that speech motor learning alters somatosensory and auditory cortical processing.

Domaines: Neurosciences

Takayuki Ito, Joshua H Coppola, David J Ostry. Neural correlates of sensory change in speech motor learning. Symposium of Sensorimotor Speech Processing, Aug 2016, Londres, United Kingdom. ⟨hal-01355875⟩