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Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance
External perturbation forces may compromise standing balance. The nervous system can intervene only after a delay greater than 100 ms, during which the body falls freely. With ageing, sensorimotor delays are prolonged, posing a critical threat to balance. We study a generic model of stabilisation wi...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897426/ https://www.ncbi.nlm.nih.gov/pubmed/31756199 http://dx.doi.org/10.1371/journal.pcbi.1007463 |
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author | Le Mouel, Charlotte Brette, Romain |
author_facet | Le Mouel, Charlotte Brette, Romain |
author_sort | Le Mouel, Charlotte |
collection | PubMed |
description | External perturbation forces may compromise standing balance. The nervous system can intervene only after a delay greater than 100 ms, during which the body falls freely. With ageing, sensorimotor delays are prolonged, posing a critical threat to balance. We study a generic model of stabilisation with neural delays to understand how the organism should adapt to challenging balance conditions. The model suggests that ankle stiffness should be increased in anticipation of perturbations, for example by muscle co-contraction, so as to slow down body fall during the neural response delay. Increased ankle muscle co-contraction is indeed observed in young adults when standing in challenging balance conditions, and in older relative to young adults during normal stance. In parallel, the analysis of the model shows that increases in either stiffness or neural delay must be coordinated with decreases in spinal sensorimotor gains, otherwise the feedback itself becomes destabilizing. Accordingly, a decrease in spinal feedback is observed in challenging conditions, and with age-related increases in neural delay. These observations have been previously interpreted as indicating an increased reliance on cortical rather than spinal control of balance, despite the fact that cortical responses have a longer latency. Our analysis challenges this interpretation by showing that these observations are consistent with a functional coadaptation of spinal feedback gains to functional changes in stiffness and neural delay. |
format | Online Article Text |
id | pubmed-6897426 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-68974262019-12-13 Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance Le Mouel, Charlotte Brette, Romain PLoS Comput Biol Research Article External perturbation forces may compromise standing balance. The nervous system can intervene only after a delay greater than 100 ms, during which the body falls freely. With ageing, sensorimotor delays are prolonged, posing a critical threat to balance. We study a generic model of stabilisation with neural delays to understand how the organism should adapt to challenging balance conditions. The model suggests that ankle stiffness should be increased in anticipation of perturbations, for example by muscle co-contraction, so as to slow down body fall during the neural response delay. Increased ankle muscle co-contraction is indeed observed in young adults when standing in challenging balance conditions, and in older relative to young adults during normal stance. In parallel, the analysis of the model shows that increases in either stiffness or neural delay must be coordinated with decreases in spinal sensorimotor gains, otherwise the feedback itself becomes destabilizing. Accordingly, a decrease in spinal feedback is observed in challenging conditions, and with age-related increases in neural delay. These observations have been previously interpreted as indicating an increased reliance on cortical rather than spinal control of balance, despite the fact that cortical responses have a longer latency. Our analysis challenges this interpretation by showing that these observations are consistent with a functional coadaptation of spinal feedback gains to functional changes in stiffness and neural delay. Public Library of Science 2019-11-22 /pmc/articles/PMC6897426/ /pubmed/31756199 http://dx.doi.org/10.1371/journal.pcbi.1007463 Text en © 2019 Le Mouel, Brette http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Le Mouel, Charlotte Brette, Romain Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title | Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title_full | Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title_fullStr | Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title_full_unstemmed | Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title_short | Anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
title_sort | anticipatory coadaptation of ankle stiffness and sensorimotor gain for standing balance |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897426/ https://www.ncbi.nlm.nih.gov/pubmed/31756199 http://dx.doi.org/10.1371/journal.pcbi.1007463 |
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