Position information but not force information is used in adapting to changes in environmental dynamics

Milner, T. E. and Hinder, M. R. (2006) Position information but not force information is used in adapting to changes in environmental dynamics. Journal of Neurophysiology, 96 2: 526-534. doi:10.1152/jn.00022.2006

Author Milner, T. E.
Hinder, M. R.
Title Position information but not force information is used in adapting to changes in environmental dynamics
Journal name Journal of Neurophysiology   Check publisher's open access policy
ISSN 0022-3077
Publication date 2006
Sub-type Article (original research)
DOI 10.1152/jn.00022.2006
Volume 96
Issue 2
Start page 526
End page 534
Total pages 9
Place of publication Bethesda
Publisher American Physiological Society
Collection year 2006
Language eng
Subject C1
321403 Motor Control
780108 Behavioural and cognitive sciences
1109 Neurosciences
1116 Medical Physiology
1702 Cognitive Sciences
Abstract This study investigated how movement error is evaluated and used to change feedforward commands following a change in the environmental dynamics. In particular, we addressed the question of whether only position-error information is used or whether information about the force-field direction can also be used for rapid adaptation to changes in the environmental dynamics. Subjects learned to move in a position-dependent force field (PF) with a parabolic profile and the dynamics of a negative spring, which produced lateral force to the left of the target hand path. They adapted very rapidly, dramatically reducing lateral error after a single trial. Several times during training, the strength of the PF was unexpectedly doubled (PF2) for two trials. This again created a large leftward deviation, which was greatly reduced on the second PF2 trial, and an aftereffect when the force field subsequently returned to its original strength. The aftereffect was abolished if the second PF2 trial was replaced by an oppositely directed velocity-dependent force field (VF). During subsequent training in the VF, immediately after having adapted to the PF, subjects applied a force that assisted the force field for similar to 15 trials, indicating that they did not use information about the force-field direction. We concluded that the CNS uses only the position error for updating the internal model of the environmental dynamics and modifying feedforward commands. Although this strategy is not necessarily optimal, it may be the most reliable strategy for iterative improvement in performance.
Keyword Neurosciences
Unstable Dynamics
Reaching Movements
Impedance Control
Motor Memory
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2007 Higher Education Research Data Collection
School of Human Movement and Nutrition Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 10 times in Scopus Article | Citations
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Created: Wed, 15 Aug 2007, 09:05:40 EST