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Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment

Short-term limb immobilization results in skeletal muscle decline, but the underlying mechanisms are incompletely understood. This study aimed to determine the neurophysiologic basis of immobilization-induced skeletal muscle decline, and whether repetitive Transcranial Magnetic Stimulation (rTMS) co...

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Autores principales: Gaffney, Christopher J., Drinkwater, Amber, Joshi, Shalmali D., O'Hanlon, Brandon, Robinson, Abbie, Sands, Kayle-Anne, Slade, Kate, Braithwaite, Jason J., Nuttall, Helen E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8107283/
https://www.ncbi.nlm.nih.gov/pubmed/33981206
http://dx.doi.org/10.3389/fnhum.2021.640642
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author Gaffney, Christopher J.
Drinkwater, Amber
Joshi, Shalmali D.
O'Hanlon, Brandon
Robinson, Abbie
Sands, Kayle-Anne
Slade, Kate
Braithwaite, Jason J.
Nuttall, Helen E.
author_facet Gaffney, Christopher J.
Drinkwater, Amber
Joshi, Shalmali D.
O'Hanlon, Brandon
Robinson, Abbie
Sands, Kayle-Anne
Slade, Kate
Braithwaite, Jason J.
Nuttall, Helen E.
author_sort Gaffney, Christopher J.
collection PubMed
description Short-term limb immobilization results in skeletal muscle decline, but the underlying mechanisms are incompletely understood. This study aimed to determine the neurophysiologic basis of immobilization-induced skeletal muscle decline, and whether repetitive Transcranial Magnetic Stimulation (rTMS) could prevent any decline. Twenty-four healthy young males (20 ± 0.5 years) underwent unilateral limb immobilization for 72 h. Subjects were randomized between daily rTMS (n = 12) using six 20 Hz pulse trains of 1.5 s duration with a 60 s inter-train-interval delivered at 90% resting Motor Threshold (rMT), or Sham rTMS (n = 12) throughout immobilization. Maximal grip strength, EMG activity, arm volume, and composition were determined at 0 and 72 h. Motor Evoked Potentials (MEPs) were determined daily throughout immobilization to index motor excitability. Immobilization induced a significant reduction in motor excitability across time (−30% at 72 h; p < 0.05). The rTMS intervention increased motor excitability at 0 h (+13%, p < 0.05). Despite daily rTMS treatment, there was still a significant reduction in motor excitability (−33% at 72 h, p < 0.05), loss in EMG activity (−23.5% at 72 h; p < 0.05), and a loss of maximal grip strength (−22%, p < 0.001) after immobilization. Interestingly, the increase in biceps (Sham vs. rTMS) (+0.8 vs. +0.1 mm, p < 0.01) and posterior forearm (+0.3 vs. +0.0 mm, p < 0.05) skinfold thickness with immobilization in Sham treatment was not observed following rTMS treatment. Reduced MEPs drive the loss of strength with immobilization. Repetitive Transcranial Magnetic Stimulation cannot prevent this loss of strength but further investigation and optimization of neuroplasticity protocols may have therapeutic benefit.
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spelling pubmed-81072832021-05-11 Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment Gaffney, Christopher J. Drinkwater, Amber Joshi, Shalmali D. O'Hanlon, Brandon Robinson, Abbie Sands, Kayle-Anne Slade, Kate Braithwaite, Jason J. Nuttall, Helen E. Front Hum Neurosci Human Neuroscience Short-term limb immobilization results in skeletal muscle decline, but the underlying mechanisms are incompletely understood. This study aimed to determine the neurophysiologic basis of immobilization-induced skeletal muscle decline, and whether repetitive Transcranial Magnetic Stimulation (rTMS) could prevent any decline. Twenty-four healthy young males (20 ± 0.5 years) underwent unilateral limb immobilization for 72 h. Subjects were randomized between daily rTMS (n = 12) using six 20 Hz pulse trains of 1.5 s duration with a 60 s inter-train-interval delivered at 90% resting Motor Threshold (rMT), or Sham rTMS (n = 12) throughout immobilization. Maximal grip strength, EMG activity, arm volume, and composition were determined at 0 and 72 h. Motor Evoked Potentials (MEPs) were determined daily throughout immobilization to index motor excitability. Immobilization induced a significant reduction in motor excitability across time (−30% at 72 h; p < 0.05). The rTMS intervention increased motor excitability at 0 h (+13%, p < 0.05). Despite daily rTMS treatment, there was still a significant reduction in motor excitability (−33% at 72 h, p < 0.05), loss in EMG activity (−23.5% at 72 h; p < 0.05), and a loss of maximal grip strength (−22%, p < 0.001) after immobilization. Interestingly, the increase in biceps (Sham vs. rTMS) (+0.8 vs. +0.1 mm, p < 0.01) and posterior forearm (+0.3 vs. +0.0 mm, p < 0.05) skinfold thickness with immobilization in Sham treatment was not observed following rTMS treatment. Reduced MEPs drive the loss of strength with immobilization. Repetitive Transcranial Magnetic Stimulation cannot prevent this loss of strength but further investigation and optimization of neuroplasticity protocols may have therapeutic benefit. Frontiers Media S.A. 2021-04-26 /pmc/articles/PMC8107283/ /pubmed/33981206 http://dx.doi.org/10.3389/fnhum.2021.640642 Text en Copyright © 2021 Gaffney, Drinkwater, Joshi, O'Hanlon, Robinson, Sands, Slade, Braithwaite and Nuttall. 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
Gaffney, Christopher J.
Drinkwater, Amber
Joshi, Shalmali D.
O'Hanlon, Brandon
Robinson, Abbie
Sands, Kayle-Anne
Slade, Kate
Braithwaite, Jason J.
Nuttall, Helen E.
Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title_full Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title_fullStr Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title_full_unstemmed Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title_short Short-Term Immobilization Promotes a Rapid Loss of Motor Evoked Potentials and Strength That Is Not Rescued by rTMS Treatment
title_sort short-term immobilization promotes a rapid loss of motor evoked potentials and strength that is not rescued by rtms treatment
topic Human Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8107283/
https://www.ncbi.nlm.nih.gov/pubmed/33981206
http://dx.doi.org/10.3389/fnhum.2021.640642
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