Title: Sensorimotor adaptation of vocal pitch is impaired in cerebellar ataxia
Legend: A: Schematic of experimental design. Top: Illustration of pitch perturbation. The pitch of participants’ produced vocalizations were shifted down by 100 cents and played back to them over headphones in essentially real time (~38 ms delay). Unperturbed productions are shown in cyan and productions with a vocal pitch perturbation in magenta Bottom: Perturbation schedule in Experiment 1, examining across-trial sensorimotor adaptation. The perturbation session (magenta) consisted of a 20-trial baseline phase with no pitch perturbation, a 40-trial exposure phase with a -100 cent perturbation, and a 20-trial washout phase with no perturbation. The control session (cyan) had veridical feedback throughout. B: Adaptation results from sustained vowel production. Top: Pitch values during vowel production in the unperturbed (solid lines) and perturbed (dashed lines) sessions. Bottom: pitch values in the perturbed session, normalized by a moving average of the unperturbed session, during vowel production. Blue indicates values for CA speakers and red indicates values for NH speakers. Shaded areas represent standard error. Gray shading indicates exposure phase. Dark green, cyan, and magenta shading represent trials used to analyze the early exposure, late exposure, and washout phases, respectively. C: Normalized pitch values produced in the perturbed session of the vowel production study in the early exposure phase (left), late exposure phase (middle), and washout phase (right). Dots and density plots represent participant means. Red stars indicate a difference from the baseline for NH; blue stars indicate a significant difference from the baseline for the CA speakers. D-E: Adaptation results from word production. As for B-C.
Citation: Slis, A. & Parrell, B. (accepted). Sensorimotor adaptation of vocal pitch is impaired in cerebellar ataxia. Journal of Cognitive Neuroscience. [preprint, bioRxiv: 10.1101/2025.10.10.681608]
Abstract: Sensory errors, mismatches between predicted sensory outcomes of movement and reafferent sensory feedback, drive changes in the feedforward control of future motor behavior that correct for those errors. Across a wide variety of motor behaviors, individuals with cerebellar damage show impairments in these corrections, strongly suggesting a key role of the cerebellum in sensorimotor adaptation. However, the extent to which the cerebellum is involved in controlling vocal pitch is currently unknown. Crucially, vocal pitch differs in several ways from other systems that suggest it relies more on feedback than feedforward control. Adaptation itself also differs in vocal pitch: rather than the gradual build-up/decay of learning seen in other systems, pitch adaptation and de-adaptation are almost immediate. Together, this questions whether adaptation in vocal pitch relies on the same mechanism as other motor domains. Here, we test the hypothesis that the cerebellum underlies sensorimotor adaptation in vocal pitch, testing the domain-generality of this neurocomputational process. In both sustained vocalization and a more natural word production task, individuals with cerebellar ataxia fail to adapt to external auditory perturbation of vocal pitch. The lack of adaptation observed, compared to the impaired but present adaptation seen in other systems, suggest that the cerebellum plays an especially critical role in maintaining accurate control of vocal pitch. Conversely, we failed to detect a previously observed increase in online compensation to vocal pitch errors in ataxia, potentially suggesting this may be an idiosyncratic change in control rather than a common trait in this population.
Investigator: Ben Parrell, PhD
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.