HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J Neurophysiol 98: 1240-1252, 2007. First published July 11, 2007; doi:10.1152/jn.00582.2007
0022-3077/07 $8.00

This Article Free upon publication Full Text Full Text (PDF) All Versions of this Article: 98/3/1240    most recent 00582.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Goble, J. A. Articles by Dounskaia, N. V. Search for Related Content PubMed PubMed Citation Articles by Goble, J. A. Articles by Dounskaia, N. V.

Directional Biases Reveal Utilization of Arm's Biomechanical Properties for Optimization of Motor Behavior

¹Harrington Department of Bioengineering, ²Department of Kinesiology, and ³Biodesign Institute, Arizona State University, Tempe, Arizona

Submitted 23 May 2007; accepted in final form 10 July 2007

Strategies used by the CNS to optimize arm movements in terms of speed, accuracy, and resistance to fatigue remain largely unknown. A hypothesis is studied that the CNS exploits biomechanical properties of multijoint limbs to increase efficiency of movement control. To test this notion, a novel free-stroke drawing task was used that instructs subjects to make straight strokes in as many different directions as possible in the horizontal plane through rotations of the elbow and shoulder joints. Despite explicit instructions to distribute strokes uniformly, subjects showed biases to move in specific directions. These biases were associated with a tendency to perform movements that included active motion at one joint and largely passive motion at the other joint, revealing a tendency to minimize intervention of muscle torque for regulation of the effect of interaction torque. Other biomechanical factors, such as inertial resistance and kinematic manipulability, were unable to adequately account for these significant biases. Also, minimizations of jerk, muscle torque change, and sum of squared muscle torque were analyzed; however, these cost functions failed to explain the observed directional biases. Collectively, these results suggest that knowledge of biomechanical cost functions regarding interaction torque (IT) regulation is available to the control system. This knowledge may be used to evaluate potential movements and to select movement of "low cost." The preference to reduce active regulation of interaction torque suggests that, in addition to muscle energy, the criterion for movement cost may include neural activity required for movement control.

This article has been cited by other articles:

				Y.-K. Kim, R. N. Hinrichs, and N. Dounskaia Multicomponent Control Strategy Underlying Production of Maximal Hand Velocity During Horizontal Arm Swing J Neurophysiol, November 1, 2009; 102(5): 2889 - 2899. [Abstract] [Full Text] [PDF]