Steen, M.C. van der (Maria Christine) (2010) Joint angle variability to control the end-effector in tool use: uncontrolled manifold analysis. thesis, Human Movement Sciences.
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Abstract
The problem at the heart of motor control is how the myriad units of the neuromotor system are coordinated to perform goal-directed movements. Recently, it has been argued that these numerous degrees of freedom (DOFs) are not redundant, but instead, should be considered as abundant in motor control, allowing flexible performance. To examine how the neuromotor system flexibly exploits DOFs in the upper extremity, we studied how variability in arm posture was employed to stabilize the displaced end-effector in tool use. Participants made pointing movements with the index finger and with an index finger extended by rods of 10, 20, and 30 em. The components of the total joint angle variance affecting whether the end-effector moved along the mean trajectory (VucM) and the variance that moved the end-effector away from the planned mean (VoRT) were computed. These computations showed that the variability in the actual joint trajectories over trials and conditions was larger than the variability that moved the end-effector away from the mean trajectory, indicating that the arm and tool were organized into a synergy. We conclude that synergies are formed during reaching with an extended end-effector. The central nervous system employs joint angles to control the end-effector independent of properties of the neuromotor system.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Bongers, Dr. R.M. |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 11:07 |
| Last Modified: | 25 Jun 2020 11:07 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/2701 |
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