Ligt, S.G.A. de (Sven) (2019) The Changes at Joint Angle Synergy Level that Underlie Changes in End-Effector Kinematics During Motor Adaptation. thesis, Human Movement Sciences.
Full text available on request.Abstract
Motor adaptation is defined as a change in motor performance following a change in task or environmental constraints, where motor performance is often described through changes in end-effector kinematics and where the end-goal of the adaptation is motor performance of a level similar to before the changes in constraints. We argue that, underlying these changes in end-effector kinematics, are changes in joint-angle synergies. To understand how changes in end-effector kinematics follow from changes in synergies, we employed a visuomotor rotation paradigm. To describe changes in end-effector kinematics we used the directional error, to assess synergistic organization of joint angles we used the UnControlled Manifold analysis and to assess changes in joint angle synergies we compared joint angle configurations that were used during visuomotor rotation trials to clusters of joint angle configurations that were used during baseline trials, where no visuomotor rotation was present. We found that the reduction in directional error during learning to adapt to a visuomotor rotation was gradual and that joint angles were organized synergistically during all experimental conditions. Joint angle configurations that were used during visuomotor rotation trials differed from the clusters of joint angle configurations that were used during the baseline, implying that new synergies emerged. Furthermore, we found that the gradual change at the level of the end-effector kinematics does not map one-to-one to the emergence of a new synergy. This suggests that motor adaptation manifests itself at joint-angle synergy level in two steps: (1) the change in constraints following the introduction of a visuomotor rotation condition lead to the emergence of a new synergy and (2) the changed interaction of constraints following the introduction of a visuomotor rotation confine the newly emerged synergy to produce the gradual change that can be observed at the level of the end-effector. Keywords: synergies, dynamical systems, adaptation, kinematics, UCM, visuomotor rotation
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Bongers, dr. R.M. and Smith, dr. J. |
| Faculty: | Medical Sciences |
| Date Deposited: | 23 May 2022 10:06 |
| Last Modified: | 23 May 2022 10:06 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3418 |
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