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Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke

The generation of isometric force at the hand can be mediated by activating a few motor modules. Stroke induces alterations in motor modules underlying steady-state isometric force generation in the human upper extremity (UE). However, how the altered motor modules impact task performance (force pro...

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Autores principales: Seo, Gang, Lee, Sang Wook, Beer, Randall F., Alamri, Amani, Wu, Yi-Ning, Raghavan, Preeti, Rymer, William Z., Roh, Jinsook
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9365968/
https://www.ncbi.nlm.nih.gov/pubmed/35967001
http://dx.doi.org/10.3389/fnhum.2022.937391
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author Seo, Gang
Lee, Sang Wook
Beer, Randall F.
Alamri, Amani
Wu, Yi-Ning
Raghavan, Preeti
Rymer, William Z.
Roh, Jinsook
author_facet Seo, Gang
Lee, Sang Wook
Beer, Randall F.
Alamri, Amani
Wu, Yi-Ning
Raghavan, Preeti
Rymer, William Z.
Roh, Jinsook
author_sort Seo, Gang
collection PubMed
description The generation of isometric force at the hand can be mediated by activating a few motor modules. Stroke induces alterations in motor modules underlying steady-state isometric force generation in the human upper extremity (UE). However, how the altered motor modules impact task performance (force production) remains unclear as stroke survivors develop and converge to the three-dimensional (3D) target force. Thus, we tested whether stroke-specific motor modules would be activated from the onset of force generation and also examined how alterations in motor modules would induce changes in force representation. During 3D isometric force development, electromyographic (EMG) signals were recorded from eight major elbow and shoulder muscles in the paretic arm of 10 chronic hemispheric stroke survivors and both arms of six age-matched control participants. A non-negative matrix factorization algorithm identified motor modules in four different time windows: three “exploratory” force ramping phases (Ramps 1–3; 0–33%, 33–67%, and 67–100% of target force magnitude, respectively) and the stable force match phase (Hold). Motor module similarity and between-force coupling were examined by calculating the scalar product and Pearson correlation across the phases. To investigate the association between the end-point force representation and the activation of the motor modules, principal component analysis (PCA) and multivariate multiple linear regression analyses were applied. In addition, the force components regressed on the activation profiles of motor modules were utilized to model the feasible force direction. Both stroke and control groups developed exploratory isometric forces with a non-linear relationship between EMG and force. During the force matching, only the stroke group showed abnormal between-force coupling in medial-lateral and backward-forward and medial-lateral and downward-upward directions. In each group, the same motor modules, including the abnormal deltoid module in stroke survivors, were expressed from the beginning of force development instead of emerging during the force exploration. The PCA and the multivariate multiple linear regression analyses showed that alterations in motor modules were associated with abnormal between-force coupling and limited feasible force direction after stroke. Overall, these results suggest that alterations in intermuscular coordination contribute to the abnormal end-point force control under isometric conditions in the UE after stroke.
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spelling pubmed-93659682022-08-12 Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke Seo, Gang Lee, Sang Wook Beer, Randall F. Alamri, Amani Wu, Yi-Ning Raghavan, Preeti Rymer, William Z. Roh, Jinsook Front Hum Neurosci Human Neuroscience The generation of isometric force at the hand can be mediated by activating a few motor modules. Stroke induces alterations in motor modules underlying steady-state isometric force generation in the human upper extremity (UE). However, how the altered motor modules impact task performance (force production) remains unclear as stroke survivors develop and converge to the three-dimensional (3D) target force. Thus, we tested whether stroke-specific motor modules would be activated from the onset of force generation and also examined how alterations in motor modules would induce changes in force representation. During 3D isometric force development, electromyographic (EMG) signals were recorded from eight major elbow and shoulder muscles in the paretic arm of 10 chronic hemispheric stroke survivors and both arms of six age-matched control participants. A non-negative matrix factorization algorithm identified motor modules in four different time windows: three “exploratory” force ramping phases (Ramps 1–3; 0–33%, 33–67%, and 67–100% of target force magnitude, respectively) and the stable force match phase (Hold). Motor module similarity and between-force coupling were examined by calculating the scalar product and Pearson correlation across the phases. To investigate the association between the end-point force representation and the activation of the motor modules, principal component analysis (PCA) and multivariate multiple linear regression analyses were applied. In addition, the force components regressed on the activation profiles of motor modules were utilized to model the feasible force direction. Both stroke and control groups developed exploratory isometric forces with a non-linear relationship between EMG and force. During the force matching, only the stroke group showed abnormal between-force coupling in medial-lateral and backward-forward and medial-lateral and downward-upward directions. In each group, the same motor modules, including the abnormal deltoid module in stroke survivors, were expressed from the beginning of force development instead of emerging during the force exploration. The PCA and the multivariate multiple linear regression analyses showed that alterations in motor modules were associated with abnormal between-force coupling and limited feasible force direction after stroke. Overall, these results suggest that alterations in intermuscular coordination contribute to the abnormal end-point force control under isometric conditions in the UE after stroke. Frontiers Media S.A. 2022-07-28 /pmc/articles/PMC9365968/ /pubmed/35967001 http://dx.doi.org/10.3389/fnhum.2022.937391 Text en Copyright © 2022 Seo, Lee, Beer, Alamri, Wu, Raghavan, Rymer and Roh. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Human Neuroscience
Seo, Gang
Lee, Sang Wook
Beer, Randall F.
Alamri, Amani
Wu, Yi-Ning
Raghavan, Preeti
Rymer, William Z.
Roh, Jinsook
Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title_full Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title_fullStr Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title_full_unstemmed Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title_short Alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
title_sort alterations in motor modules and their contribution to limitations in force control in the upper extremity after stroke
topic Human Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9365968/
https://www.ncbi.nlm.nih.gov/pubmed/35967001
http://dx.doi.org/10.3389/fnhum.2022.937391
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