caa a22 4500 445353090 CHVBK 20180317142850.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s00221-011-2541-2 doi (NATIONALLICENCE)springer-10.1007/s00221-011-2541-2 Motor equivalence and self-motion induced by different movement speeds [Elektronische Daten] [J. Scholz, T. Dwight-Higgin, J. Lynch, Y. Tseng, V. Martin, G. Schöner] This study investigated pointing movements in 3D asking two questions: (1) Is goal-directed reaching accompanied by self-motion, a component of the joint velocity vector that leaves the hand's movement unaffected? (2) Are differences in the terminal joint configurations among different speeds of reaching motor equivalent (i.e., terminal joint configurations differ more in directions of joint space that do not produce different pointer-tip positions than in directions that do) or non-motor equivalent (i.e., terminal joint configurations differ equally or more in directions of joint space that lead to different pointer-tip positions than in directions that do not affect the pointer-tip position). Subjects reached from an identical starting joint configuration and pointer-tip location to targets at slow, moderate, and fast speeds. Ten degrees of freedom of joint motion of the arm were recorded. The relationship between changes in the joint configuration and the three-dimensional pointer-tip position was expressed by a standard kinematic model, and the range- and null subspaces were computed from the associated Jacobian matrix. (1) The joint velocity vector and (2) the difference vector between terminal joint configurations from pairs of speed conditions were projected into the two subspaces. The relative length of the two components was used to quantify the amount of self-motion and the presence of motor equivalence, respectively. Results revealed that reaches were accompanied by a significant amount of self-motion at all reaching speeds. Self-motion scaled with movement speed. In addition, the difference in the terminal joint configuration between pairs of different reaching speeds revealed motor equivalence. The results are consistent with a control system that takes advantage of motor redundancy, allowing for flexibility in the face of perturbations, here induced by different movement speeds. Springer-Verlag, 2011 Reaching nationallicence Motor Control nationallicence Motor equivalence nationallicence Movement velocity nationallicence Scholz J. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut Dwight-Higgin T. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut Lynch J. Department of Biology, University of Delaware, 19716, Newark, DE, USA aut Tseng Y. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut Martin V. Institut für Neuroinformatik NB 3/31, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany aut Schöner G. Institut für Neuroinformatik NB 3/31, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany aut Experimental Brain Research Springer-Verlag 209/3(2011-03-01), 319-332 0014-4819 209:3<319 2011 209 221 https://doi.org/10.1007/s00221-011-2541-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00221-011-2541-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Scholz J. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut NATIONALLICENCE 700 1- Dwight-Higgin T. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut NATIONALLICENCE 700 1- Lynch J. Department of Biology, University of Delaware, 19716, Newark, DE, USA aut NATIONALLICENCE 700 1- Tseng Y. Physical Therapy Department, University of Delaware, 19716, Newark, DE, USA aut NATIONALLICENCE 700 1- Martin V. Institut für Neuroinformatik NB 3/31, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany aut NATIONALLICENCE 700 1- Schöner G. Institut für Neuroinformatik NB 3/31, Ruhr-Universität Bochum, Universitätsstr. 150, 44801, Bochum, Germany aut NATIONALLICENCE 773 0- Experimental Brain Research Springer-Verlag 209/3(2011-03-01), 319-332 0014-4819 209:3<319 2011 209 221 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer