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Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation

When moving grasped objects, people automatically modulate grip force (GF) with movement-dependent load force (LF) in order to prevent object slip. However, GF can also be modulated voluntarily as when squeezing an object. Here we investigated possible interactions between automatic and voluntary GF...

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Autor principal: Danion, Frederic
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823659/
https://www.ncbi.nlm.nih.gov/pubmed/24244483
http://dx.doi.org/10.1371/journal.pone.0079341
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author Danion, Frederic
author_facet Danion, Frederic
author_sort Danion, Frederic
collection PubMed
description When moving grasped objects, people automatically modulate grip force (GF) with movement-dependent load force (LF) in order to prevent object slip. However, GF can also be modulated voluntarily as when squeezing an object. Here we investigated possible interactions between automatic and voluntary GF control. Participants were asked to generate horizontal cyclic movements (between 0.6 and 2.0 Hz) of a hand-held object that was restrained by an elastic band such that the load force (LF) reached a peak once per movement cycle, and to simultaneously squeeze the object at each movement reversal (i.e., twice per cycle). Participants also performed two control tasks in which they either only moved (between 0.6 and 2.0 Hz) or squeezed (between 1.2 and 4.0 Hz) the object. The extent to which GF modulation in the simultaneous task could be predicted from the two control tasks was assessed using power spectral analyses. At all frequencies, the GF power spectra from the simultaneous task exhibited two prominent components that occurred at the cycle frequency (ƒ) and at twice this frequency (2ƒ), whereas the spectra from the movement and squeeze control task exhibited only single peaks at ƒ and 2ƒ, respectively. At lower frequencies, the magnitudes of both frequency components in the simultaneous task were similar to the magnitudes of the corresponding components in the control tasks. However, as frequency increased, the magnitudes of both components in the simultaneous task were greater than the magnitudes of the corresponding control task components. Moreover, the phase relationship between the ƒ components of GF and LF began to drift from the value observed in the movement control task. Overall these results suggest that, at lower movement frequencies, voluntary and automatic GF control processes operate at different hierarchical levels. Several mechanisms are discussed to account for interaction effects observed at higher movement frequencies.
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spelling pubmed-38236592013-11-15 Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation Danion, Frederic PLoS One Research Article When moving grasped objects, people automatically modulate grip force (GF) with movement-dependent load force (LF) in order to prevent object slip. However, GF can also be modulated voluntarily as when squeezing an object. Here we investigated possible interactions between automatic and voluntary GF control. Participants were asked to generate horizontal cyclic movements (between 0.6 and 2.0 Hz) of a hand-held object that was restrained by an elastic band such that the load force (LF) reached a peak once per movement cycle, and to simultaneously squeeze the object at each movement reversal (i.e., twice per cycle). Participants also performed two control tasks in which they either only moved (between 0.6 and 2.0 Hz) or squeezed (between 1.2 and 4.0 Hz) the object. The extent to which GF modulation in the simultaneous task could be predicted from the two control tasks was assessed using power spectral analyses. At all frequencies, the GF power spectra from the simultaneous task exhibited two prominent components that occurred at the cycle frequency (ƒ) and at twice this frequency (2ƒ), whereas the spectra from the movement and squeeze control task exhibited only single peaks at ƒ and 2ƒ, respectively. At lower frequencies, the magnitudes of both frequency components in the simultaneous task were similar to the magnitudes of the corresponding components in the control tasks. However, as frequency increased, the magnitudes of both components in the simultaneous task were greater than the magnitudes of the corresponding control task components. Moreover, the phase relationship between the ƒ components of GF and LF began to drift from the value observed in the movement control task. Overall these results suggest that, at lower movement frequencies, voluntary and automatic GF control processes operate at different hierarchical levels. Several mechanisms are discussed to account for interaction effects observed at higher movement frequencies. Public Library of Science 2013-11-11 /pmc/articles/PMC3823659/ /pubmed/24244483 http://dx.doi.org/10.1371/journal.pone.0079341 Text en © 2013 Frederic Danion http://creativecommons.org/licenses/by/4.0/ 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 properly credited.
spellingShingle Research Article
Danion, Frederic
Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title_full Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title_fullStr Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title_full_unstemmed Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title_short Superposition of Automatic and Voluntary Aspects of Grip Force Control in Humans during Object Manipulation
title_sort superposition of automatic and voluntary aspects of grip force control in humans during object manipulation
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823659/
https://www.ncbi.nlm.nih.gov/pubmed/24244483
http://dx.doi.org/10.1371/journal.pone.0079341
work_keys_str_mv AT danionfrederic superpositionofautomaticandvoluntaryaspectsofgripforcecontrolinhumansduringobjectmanipulation