The Synergistic Organization of Muscle Recruitment Constrains Visuomotor Adaptation

Aymar De Rugy, Mark R. Hinder, Daniel G. Woolley, Richard G. Carson

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Reaching to visual targets engages the nervous system in a series of transformations between sensory information and motor commands. That which remains to be determined is the extent to which the processes that mediate sensorimotor adaptation to novel environments engage neural circuits that represent the required movement in joint-based or muscle-based coordinate systems. We sought to establish the contribution of these alternative representations to the process of visuomotor adaptation. To do so we applied a visuomotor rotation during a center-out isometric torque production task that involved flexion/extension and supination/pronation at the elbow-joint complex. In separate sessions, distinct half-quadrant rotations (i.e., 45°) were applied such that adaptation could be achieved either by only rescaling the individual joint torques (i.e., the visual target and torque target remained in the same quadrant) or by additionally requiring torque reversal at a contributing joint (i.e., the visual target and torque target were in different quadrants). Analysis of the time course of directional errors revealed that the degree of adaptation was lower (by ~20%) when reversals in the direction of joint torques were required. It has been established previously that in this task space, a transition between supination and pronation requires the engagement of a different set of muscle synergists, whereas in a transition between flexion and extension no such change is required. The additional observation that the initial level of adaptation was lower and the subsequent aftereffects were smaller, for trials that involved a pronation–supination transition than for those that involved a flexion–extension transition, supports the conclusion that the process of adaptation engaged, at least in part, neural circuits that represent the required motor output in a muscle-based coordinate system.
Original languageEnglish
Pages (from-to)2263-2269
Number of pages7
JournalJournal of Neurophysiology
Volume101
Issue number5
Early online date18 Feb 2009
DOIs
Publication statusPublished - 01 May 2009

Bibliographical note

Australian Research Council ARCDP0770982

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

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