Ben Parrell, PhD – Slide of the Week

Ben Parrell, PhD - Slide of the Week

Title: A single exposure to altered auditory feedback causes observable sensorimotor adaptation in speech

Legend: A) Schematic of auditory feedback alteration. Participant’s vowel formants (resonances of the vocal tract that distinguish between vowels) are altered in real time and played back to them over headphones. B) Example trial schedule. Upward and downward perturbations of the first vowel formant (F1) are applied quasi-randomly, interleaved with unperturbed trials. Adaptation of vowel formants following a single exposure to a perturbation is measured by comparing trials immediately before a perturbation with trials immediately after that perturbation. C) Normalized formant trajectories during perturbated trial (left) and trials immediately following perturbed trials (right). On perturbed trials, a compensatory feedback response to oppose the perturbation begins ~100 ms after vowel onset, and is measured from 120-250 ms. On unperturbed trials, formant values are notably different from 0 during the early portion (0-100ms) of the vowel. D) F1 values for perturbed trials (left, measuring online compensation) and trials immediately following the perturbation (right, measuring single-trial adaptation). Confirming previous work, compensation values for upward and downward perturbations are significantly different from each other and from 0. Single-exposure adaptation values are smaller in magnitude, but still show a significant difference between upward and downward perturbations, showing that adaptation to altered auditory feedback in speech occurs after a single exposure.

Citation: Hantzsch, L., Parrell, B., & Niziolek, C. A. (2022). A single exposure to altered auditory feedback causes observable sensorimotor adaptation in speech. eLife, 11, e73694.

Abstract: Sensory errors induce two types of behavioral changes: rapid compensation within a movement and longer-term adaptation of subsequent movements. Although adaptation is hypothesized to occur whenever a sensory error is perceived (including after a single exposure to altered feedback), adaptation of articulatory movements in speech has only been observed after repeated exposure to auditory perturbations, questioning both current theories of speech sensorimotor adaptation and the universality of more general theories of adaptation. We measured single-exposure or ‘one-shot’ learning in a large dataset in which participants were exposed to intermittent, unpredictable perturbations of their speech acoustics. On unperturbed trials immediately following these perturbed trials, participants adjusted their speech to oppose the preceding shift, demonstrating that learning occurs even after a single exposure to auditory error. These results provide critical support for current theories of sensorimotor adaptation in speech and align speech more closely with learning in other motor domains.

About the Lab: The Speech Motor Action + Control Lab investigates the human capacity to produce speech using behavioral, computation, and neurological methods. Our current projects focus on the role of the cerebellum in speech motor control and speech disorders associated with cerebellar damage by using computational models to understand the architecture of the speech motor system and investigating how speech motor control is updated and altered through various types of learning.

Investigator: Ben Parrell, PhD

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