Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control
A muscle synergy is a coordinative structure of muscles that has been proposed as a strategy to reduce the number of variables that the central nervous system (CNS) has to address in motor tasks. In this article, the mechanical contribution of muscle synergies and coordinative structures of muscles...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-08-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnhum.2017.00434/full |
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| author | Akari Kubo Shota Hagio Shota Hagio Benio Kibushi Benio Kibushi Toshio Moritani Motoki Kouzaki |
| author_facet | Akari Kubo Shota Hagio Shota Hagio Benio Kibushi Benio Kibushi Toshio Moritani Motoki Kouzaki |
| author_sort | Akari Kubo |
| collection | DOAJ |
| description | A muscle synergy is a coordinative structure of muscles that has been proposed as a strategy to reduce the number of variables that the central nervous system (CNS) has to address in motor tasks. In this article, the mechanical contribution of muscle synergies and coordinative structures of muscles in voluntary multi-directional postural control were investigated. The task for healthy, young subjects was to shift and align their center of pressure (COP) to targets dispersed in 12 different directions in the horizontal plane by leaning their bodies for 10 s. Electromyograms (EMGs) of 18 muscles and COPs were recorded in the experiment. Muscle synergies were extracted using non-negative matrix factorization (NMF), and the structure of coordinative modules to keep the posture leaning toward various directions was disclosed. Then the directional properties, such as the mechanical role (i.e., action directions, we use ADs as abbreviation below), of muscle synergies and muscles were estimated using an electromyogram-weighted averaging (EWA) method, which is based on a cross-correlation between the fluctuations in the activation of muscle synergies and the COP. The results revealed that the ADs of muscle synergies were almost uniformly distributed in the task space in most of the subjects, which indicates that mechanical characteristics reduce the redundancy in postural control. In terms of the composition of muscle synergies and the ADs of individual muscles, we confirmed that muscle synergies in multi-directional postural control comprised a combination of several muscles, including various ADs, that generate torque at different joints. |
| first_indexed | 2024-12-10T06:56:39Z |
| format | Article |
| id | doaj.art-a3b2bdc437c847649aacbb3afd831657 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-10T06:56:39Z |
| publishDate | 2017-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-a3b2bdc437c847649aacbb3afd8316572022-12-22T01:58:25ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612017-08-011110.3389/fnhum.2017.00434281058Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural ControlAkari Kubo0Shota Hagio1Shota Hagio2Benio Kibushi3Benio Kibushi4Toshio Moritani5Motoki Kouzaki6Laboratory of Neurophysiology, Graduate School of Human and Environmental Studies, Kyoto UniversityKyoto, JapanJapan Society for the Promotion of ScienceTokyo, JapanGraduate School of Education, The University of TokyoTokyo, JapanLaboratory of Neurophysiology, Graduate School of Human and Environmental Studies, Kyoto UniversityKyoto, JapanJapan Society for the Promotion of ScienceTokyo, JapanSchool of Health and Sport Sciences, Chukyo UniversityNagoya, JapanLaboratory of Neurophysiology, Graduate School of Human and Environmental Studies, Kyoto UniversityKyoto, JapanA muscle synergy is a coordinative structure of muscles that has been proposed as a strategy to reduce the number of variables that the central nervous system (CNS) has to address in motor tasks. In this article, the mechanical contribution of muscle synergies and coordinative structures of muscles in voluntary multi-directional postural control were investigated. The task for healthy, young subjects was to shift and align their center of pressure (COP) to targets dispersed in 12 different directions in the horizontal plane by leaning their bodies for 10 s. Electromyograms (EMGs) of 18 muscles and COPs were recorded in the experiment. Muscle synergies were extracted using non-negative matrix factorization (NMF), and the structure of coordinative modules to keep the posture leaning toward various directions was disclosed. Then the directional properties, such as the mechanical role (i.e., action directions, we use ADs as abbreviation below), of muscle synergies and muscles were estimated using an electromyogram-weighted averaging (EWA) method, which is based on a cross-correlation between the fluctuations in the activation of muscle synergies and the COP. The results revealed that the ADs of muscle synergies were almost uniformly distributed in the task space in most of the subjects, which indicates that mechanical characteristics reduce the redundancy in postural control. In terms of the composition of muscle synergies and the ADs of individual muscles, we confirmed that muscle synergies in multi-directional postural control comprised a combination of several muscles, including various ADs, that generate torque at different joints.http://journal.frontiersin.org/article/10.3389/fnhum.2017.00434/fullcenter of pressureelectromyogram-weighted averaging methodmotor controlmuscle synergynon-negative matrix factorization |
| spellingShingle | Akari Kubo Shota Hagio Shota Hagio Benio Kibushi Benio Kibushi Toshio Moritani Motoki Kouzaki Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control Frontiers in Human Neuroscience center of pressure electromyogram-weighted averaging method motor control muscle synergy non-negative matrix factorization |
| title | Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control |
| title_full | Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control |
| title_fullStr | Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control |
| title_full_unstemmed | Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control |
| title_short | Action Direction of Muscle Synergies in Voluntary Multi-Directional Postural Control |
| title_sort | action direction of muscle synergies in voluntary multi directional postural control |
| topic | center of pressure electromyogram-weighted averaging method motor control muscle synergy non-negative matrix factorization |
| url | http://journal.frontiersin.org/article/10.3389/fnhum.2017.00434/full |
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