How Variability and Effort Determine Coordination at Large Forces
File(s)
Author(s)
Kolossiatis, M
Charalambous, T
Burdet, E
Type
Journal Article
Abstract
Motor control is a challenging task for the central nervous system, since it involves redundant degrees of freedom, nonlinear dynamics of actuators and limbs, as well as noise. When an action is carried out, which factors does your nervous system consider to determine the appropriate set of muscle forces between redundant degrees-of-freedom? Important factors determining motor output likely encompass effort and the resulting motor noise. However, the tasks used in many previous motor control studies could not identify these two factors uniquely, as signal-dependent noise monotonically increases as a function of the effort. To address this, a recent paper introduced a force control paradigm involving one finger in each hand that can disambiguate these two factors. It showed that the central nervous system considers both force noise and amplitude, with a larger weight on the absolute force and lower weights on both noise and normalized force. While these results are valid for the relatively low force range considered in that paper, the magnitude of the force shared between the fingers for large forces is not known. This paper investigates this question experimentally, and develops an appropriate Markov chain Monte Carlo method in order to estimate the weightings given to these factors. Our results demonstrate that the force sharing strongly depends on the force level required, so that for higher force levels the normalized force is considered as much as the absolute force, whereas the role of noise minimization becomes negligible.
Date Issued
2016-03-02
Date Acceptance
2016-02-01
Citation
PLOS One, 2016, 11 (3)
ISSN
1932-6203
Publisher
Public Library of Science
Journal / Book Title
PLOS One
Volume
11
Issue
3
Copyright Statement
© 2016 Kolossiatis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
License URL
Sponsor
Commission of the European Communities
Commission of the European Communities
Commission of the European Communities
Commission of the European Communities
Commission of the European Communities
Grant Number
231724
PITN-GA-2012-317488
601003
611626
644727
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
LEAST-SQUARES
SYNERGIES
Adult
Central Nervous System
Female
Fingers
Hand Strength
Humans
Male
Muscle Contraction
Muscle, Skeletal
Psychomotor Performance
Young Adult
General Science & Technology
MD Multidisciplinary
Publication Status
Published
Article Number
e0149512