Warning: A non-numeric value encountered in /home/public/export/export_srwxml.php on line 32
Warning: Cannot modify header information - headers already sent by (output started at /home/public/export/export_srwxml.php:32) in /home/public/includes/include.inc.php on line 5344
1.1
1
xml
info:srw/schema/1/mods-v3.2
A computational model for redundant human three-dimensional pointing movements: integration of independent spatial and temporal motor plans simplifies movement dynamics
Biess
A
author
Liebermann
D
G
author
Flash
T
author
2007
English
Few computational models have addressed the spatiotemporal features of unconstrained three-dimensional (3D) arm motion. Empirical observations made on hand paths, speed profiles, and arm postures during point-to-point movements led to the assumption that hand path and arm posture are independent of movement speed, suggesting that the geometric and temporal properties of movements are decoupled. In this study, we present a computational model of 3D movements for an arm with four degrees of freedom based on the assumption that optimization principles are separately applied at the geometric and temporal levels of control. Geometric properties (path and posture) are defined in terms of geodesic paths with respect to the kinetic energy metric in the Riemannian configuration space. Accordingly, a geodesic path can be generated with less muscular effort than on any other, nongeodesic path, because the sum of all configuration-speed-dependent torques vanishes. The temporal properties of the movement (speed) are determined in task space by minimizing the squared jerk along the selected end-effector path. The integration of both planning levels into a single spatiotemporal representation simplifies the control of arm dynamics along geodesic paths and results in movements with near minimal torque change and minimal peak value of kinetic energy. Thus, the application of Riemannian geometry allows for a reconciliation of computational models previously proposed for the description of arm movements. We suggest that geodesics are an emergent property of the motor system through the exploration of dynamical space. Our data validated the predictions for joint trajectories, hand paths, final postures, speed profiles, and driving torques.
Analysis of Variance
Arm/physiology
Biomechanics
*Computer Simulation
Humans
*Models
Biological
Movement/*physiology
*Nonlinear Dynamics
Posture/physiology
Psychomotor Performance/*physiology
Range of Motion
Articular/physiology
Reaction Time/physiology
Space Perception/*physiology
Time Factors
Torque
PMID:18045899
exported from refbase (https://refbase.nfshost.com/show.php?record=35), last updated on Mon, 31 Dec 2012 14:28:04 +0000
text
http://www.ncbi.nlm.nih.gov/pubmed/18045899
http://www.ncbi.nlm.nih.gov/pubmed/18045899
10.1523/JNEUROSCI.4334-06.2007
18045899
Biess_etal2007
The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
J Neurosci
2007
continuing
periodical
academic journal
27
48
13045
13064
0270-6474
1