Enhanced crosslimb transfer of force-field learning for dynamics that are identical in extrinsic and joint-based coordinates for both limbs
Journal of Neurophysiology. 2016-01-01; 115(1): 445-456
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1. J Neurophysiol. 2016 Jan 1;115(1):445-56. doi: 10.1152/jn.00485.2015. Epub 2015
Enhanced crosslimb transfer of force-field learning for dynamics that are
identical in extrinsic and joint-based coordinates for both limbs.
Carroll TJ(1), de Rugy A(2), Howard IS(3), Ingram JN(4), Wolpert DM(4).
(1)Centre for Sensorimotor Performance, School of Human Movement and Nutrition
Sciences, The University of Queensland, Brisbane, Australia;
(2)Centre for Sensorimotor Performance, School of Human Movement and Nutrition
Sciences, The University of Queensland, Brisbane, Australia; Institut de
Neurosciences Cognitives et Intégratives d’Aquitaine, Centre National de la
Recherche Scientifique Unité Mixte de Recherche 5287, Université de Bordeaux,
(3)School of Computing and Mathematics, Plymouth University, Plymouth, United
(4)Computational and Biological Learning Laboratory, Department of Engineering,
University of Cambridge, Cambridge, United Kingdom.
Humans are able to adapt their motor commands to make accurate movements in novel
sensorimotor environments, such as when wielding tools that alter limb dynamics.
However, it is unclear to what extent sensorimotor representations, obtained
through experience with one limb, are available to the opposite, untrained limb
and in which form they are available. Here, we compared crosslimb transfer of
force-field compensation after participants adapted to a velocity-dependent curl
field, oriented either in the sagittal or the transverse plane. Due to the mirror
symmetry of the limbs, the force field had identical effects for both limbs in
joint and extrinsic coordinates in the sagittal plane but conflicting joint-based
effects in the transverse plane. The degree of force-field compensation exhibited
by the opposite arm in probe trials immediately after initial learning was
significantly greater after sagittal (26 ± 5%) than transverse plane adaptation
(9 ± 4%; P < 0.001), irrespective of whether participants learned initially with
the left or the right arm or via abrupt or gradual exposure to the force field.
Thus transfer was impaired when the orientation of imposed dynamics conflicted in
intrinsic coordinates for the two limbs. The data reveal that neural
representations of novel dynamics are only partially available to the opposite
limb, since transfer is incomplete even when force-field perturbation is
spatially compatible for the two limbs, according to both intrinsic and extrinsic
Copyright © 2016 the American Physiological Society.
PMID: 26581867 [Indexed for MEDLINE]