Schotborgh, A.K. (2021) Recalibration of synergies during the visuomotor adaptation task. thesis, Human Movement Sciences.
Full text available on request.Abstract
In the current study, sensorimotor learning is approached as a recalibration between the available perceptual information and synergies that underly goal-directed movements, with the primary focus on how the synergies are altered (Warren, 2006; Withagen & Michaels, 2002). Synergies are defined as temporary links between the abundant degrees of freedom (DOFs) and are operationalized by containing more variability in the degrees of freedom that stabilizes the desired performance (Vucm, i.e., covarition) than variability that leads to a deviation from the desired outcome (Vort) (Profeta & Turvey, 2018; Riley et al., 2011; Scholz & Schöner, 1999). The recalibration process was studied with the visuomotor adaptation task in which a rotation of 45 degrees is applied to the visual information during the adaptation phase and later removed during the wash-out phase (Krakauer et al., 2019). These changes in available perceptual information result in strongly curved reaching movements that participants try to adopt towards nearly straight reaching movements that they performed during the baseline phase. The objective of the current study is to confirm that synergies underly the reaching movements and to examine how the synergies are altered in the adaptation and wash-out phase to achieve recalibration. The findings confirmed recalibration of the end-effector apparent in nearly straight line reaching movements at the end of the adaptation and wash-out phase. Furthermore, a synergistic organization was present in all reaching movements (i.e., Vucm was larger than Vort) and synergies were adopted during the adaptation and wash-out phase by respectively an increase and decrease of total amount of variance. Hence, our findings imply that different recalibration processes take place between the synergies and the available perceptual information during the adaptation and wash-out phase. We suggest that during the adaptation phase high values of variance are present to allow for the search of the action system to move out of existing motor solutions congruent with the baseline phase and to find new joint angle combinations to perform the reaching movements during the adaptation phase (called motor exploration, Davids et al., 2006; Lee et al., 2017). On the contrary, the total amount of variance is limited in the synergy during the wash-out phase as recalibration reflects the purpose of increasing the precision of reaching the target (similar to the baseline phase) (Cardis et al., 2018; Ranganathan & Newell, 2010a, 2010b). Keywords: ecological-dynamical approach, recalibration, synergies, visuomotor adaptation task, motor exploration
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Bongers, dr. R. |
| Faculty: | Medical Sciences |
| Date Deposited: | 13 May 2022 14:32 |
| Last Modified: | 13 May 2022 14:32 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3317 |
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