The Sensorimotor System Modulates Muscular Co-Contraction Relative to Visuomotor Feedback Responses to Regulate Movement Variability
Journal of Neurophysiology
The naturally occurring variability in our movements often poses a significant challenge when attempting to produce precise and accurate actions, which is readily evident when playing a game of darts. Two differing, yet potentially complementary, control strategies that the sensorimotor system may use to regulate movement variability are impedance control and feedback control. Greater muscular co-contraction leads to greater impedance that acts to stabilize the hand, while visuomotor feedback responses can be used to rapidly correct for unexpected deviations when reaching toward a target. Here, we examined the independent roles and potential interplay of impedance control and visuomotor feedback control when regulating movement variability. Participants were instructed to perform a precise reaching task by moving a cursor through a narrow visual channel. We manipulated cursor feedback by visually amplifying movement variability and/or delaying the visual feedback of the cursor. We found that participants decreased movement variability by increasing muscular co-contraction, aligned with an impedance control strategy. Participants displayed visuomotor feedback responses during the task but, unexpectedly, there was no modulation between conditions. However, we did find a relationship between muscular co-contraction and visuomotor feedback responses, suggesting that participants modulated impedance control relative to feedback control. Taken together, our results highlight that the sensorimotor system modulates muscular co-contraction, relative to visuomotor feedback responses, to regulate movement variability and produce accurate actions. NEW & NOTEWORTHY: The sensorimotor system has the constant challenge of dealing with the naturally occurring variability in our movements. Here, we investigated the potential roles of muscular co-contraction and visuomotor feedback responses to regulate movement variability. When we visually amplified movements, we found that the sensorimotor system primarily uses muscular co-contraction to regulate movement variability. Interestingly, we found that muscular co-contraction was modulated relative to inherent visuomotor feedback responses, suggesting an interplay between impedance and feedback control.
Copyright © 2023 the American Physiological Society. This is the Accepted Manuscript version of Calalo, Jan A., Adam M. Roth, Rakshith Lokesh, Seth R. Sullivan, Jeremy D. Wong, Jennifer A. Semrau, and Joshua G. A. Cashaback. “The Sensorimotor System Modulates Muscular Co-Contraction Relative to Visuomotor Feedback Responses to Regulate Movement Variability.” Journal of Neurophysiology 129, no. 4 (April 1, 2023): 751–66. https://doi.org/10.1152/jn.00472.2022.. This article was originally published in Journal of Neurophysiology. The version of record is available at: https://doi.org/10.1152/jn.00472.2022. This article will be embargoed until 04/01/2024.
co-contraction, feedback, impedance, movement variability, visuomotor
Calalo, Jan A., Adam M. Roth, Rakshith Lokesh, Seth R. Sullivan, Jeremy D. Wong, Jennifer A. Semrau, and Joshua G. A. Cashaback. “The Sensorimotor System Modulates Muscular Co-Contraction Relative to Visuomotor Feedback Responses to Regulate Movement Variability.” Journal of Neurophysiology 129, no. 4 (April 1, 2023): 751–66. https://doi.org/10.1152/jn.00472.2022.