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Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking

We have previously described a modular organization of the locomotor step cycle in the cat in which a number of sparse synergies are activated sequentially during the swing phase of the step cycle (Krouchev et al., 2006). Here, we address how these synergies are modified during voluntary gait modifi...

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Autores principales: Krouchev, Nedialko, Drew, Trevor
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708143/
https://www.ncbi.nlm.nih.gov/pubmed/23874287
http://dx.doi.org/10.3389/fncom.2013.00083
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author Krouchev, Nedialko
Drew, Trevor
author_facet Krouchev, Nedialko
Drew, Trevor
author_sort Krouchev, Nedialko
collection PubMed
description We have previously described a modular organization of the locomotor step cycle in the cat in which a number of sparse synergies are activated sequentially during the swing phase of the step cycle (Krouchev et al., 2006). Here, we address how these synergies are modified during voluntary gait modifications. Data were analysed from 27 bursts of muscle activity (recorded from 18 muscles) recorded in the forelimb of the cat during locomotion. These were grouped into 10 clusters, or synergies, during unobstructed locomotion. Each synergy was comprised of only a small number of muscles bursts (sparse synergies), some of which included both proximal and distal muscles. Eight (8/10) of these synergies were active during the swing phase of locomotion. Synergies observed during the gait modifications were very similar to those observed during unobstructed locomotion. Constraining these synergies to be identical in both the lead (first forelimb to pass over the obstacle) and the trail (second limb) conditions allowed us to compare the changes in phase and magnitude of the synergies required to modify gait. In the lead condition, changes were observed particularly in those synergies responsible for transport of the limb and preparation for landing. During the trail condition, changes were particularly evident in those synergies responsible for lifting the limb from the ground at the onset of the swing phase. These changes in phase and magnitude were adapted to the size and shape of the obstacle over which the cat stepped. These results demonstrate that by modifying the phase and magnitude of a finite number of muscle synergies, each comprised of a small number of simultaneously active muscles, descending control signals could produce very specific modifications in limb trajectory during locomotion. We discuss the possibility that these changes in phase and magnitude could be produced by changes in the activity of neurones in the motor cortex.
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spelling pubmed-37081432013-07-19 Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking Krouchev, Nedialko Drew, Trevor Front Comput Neurosci Neuroscience We have previously described a modular organization of the locomotor step cycle in the cat in which a number of sparse synergies are activated sequentially during the swing phase of the step cycle (Krouchev et al., 2006). Here, we address how these synergies are modified during voluntary gait modifications. Data were analysed from 27 bursts of muscle activity (recorded from 18 muscles) recorded in the forelimb of the cat during locomotion. These were grouped into 10 clusters, or synergies, during unobstructed locomotion. Each synergy was comprised of only a small number of muscles bursts (sparse synergies), some of which included both proximal and distal muscles. Eight (8/10) of these synergies were active during the swing phase of locomotion. Synergies observed during the gait modifications were very similar to those observed during unobstructed locomotion. Constraining these synergies to be identical in both the lead (first forelimb to pass over the obstacle) and the trail (second limb) conditions allowed us to compare the changes in phase and magnitude of the synergies required to modify gait. In the lead condition, changes were observed particularly in those synergies responsible for transport of the limb and preparation for landing. During the trail condition, changes were particularly evident in those synergies responsible for lifting the limb from the ground at the onset of the swing phase. These changes in phase and magnitude were adapted to the size and shape of the obstacle over which the cat stepped. These results demonstrate that by modifying the phase and magnitude of a finite number of muscle synergies, each comprised of a small number of simultaneously active muscles, descending control signals could produce very specific modifications in limb trajectory during locomotion. We discuss the possibility that these changes in phase and magnitude could be produced by changes in the activity of neurones in the motor cortex. Frontiers Media S.A. 2013-07-11 /pmc/articles/PMC3708143/ /pubmed/23874287 http://dx.doi.org/10.3389/fncom.2013.00083 Text en Copyright © 2013 Krouchev and Drew. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
spellingShingle Neuroscience
Krouchev, Nedialko
Drew, Trevor
Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title_full Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title_fullStr Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title_full_unstemmed Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title_short Motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
title_sort motor cortical regulation of sparse synergies provides a framework for the flexible control of precision walking
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708143/
https://www.ncbi.nlm.nih.gov/pubmed/23874287
http://dx.doi.org/10.3389/fncom.2013.00083
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