Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.

The present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC) in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature i...

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Main Authors: Francesco Budini, Lara M McManus, Marika Berchicci, Federica Menotti, Andrea Macaluso, Francesco Di Russo, Madeleine M Lowery, Giuseppe De Vito
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0115012&type=printable
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author Francesco Budini
Lara M McManus
Marika Berchicci
Federica Menotti
Andrea Macaluso
Francesco Di Russo
Madeleine M Lowery
Giuseppe De Vito
author_facet Francesco Budini
Lara M McManus
Marika Berchicci
Federica Menotti
Andrea Macaluso
Francesco Di Russo
Madeleine M Lowery
Giuseppe De Vito
author_sort Francesco Budini
collection DOAJ
description The present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC) in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature in patients affected by pathological tremors; understanding its mechanisms is therefore important. Thirteen healthy volunteers (23±4 years) performed elbow flexor sustained contractions both against a spring load and in isometric conditions at 20% of maximal voluntary isometric contraction (MVC). Spring stiffness was selected to induce instability in the stretch reflex servo loop. 64 EEG channels, surface EMG from the biceps brachii muscle and force were simultaneously recorded. Contractions against the spring resulted in greater fluctuations of the force signal and EMG amplitude compared to isometric conditions (p<.05). During isometric contractions CMC was systematically found in the beta band and sporadically observed in the alpha band. However, during the contractions against the spring load, CMC in the alpha band was observed in 12 out of 13 volunteers. Partial directed coherence (PDC) revealed an increased information flow in the EMG to EEG direction in the alpha band (p<.05). Therefore, coherence in the alpha band between the sensory-motor cortex and the biceps brachii muscle can be systematically induced in healthy individuals by mechanically amplifying tremor. The increased information flow in the EMG to EEG direction may reflect enhanced afferent activity from the muscle spindles. These results may contribute to the understanding of the presence of alpha band CMC in tremor related pathologies by suggesting that the origin of this phenomenon may not only be at cortical level but may also be affected by spinal circuit loops.
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spelling doaj-art-677439b0a4cc4c44b3a283f0dbf474562025-08-20T03:00:27ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01912e11501210.1371/journal.pone.0115012Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.Francesco BudiniLara M McManusMarika BerchicciFederica MenottiAndrea MacalusoFrancesco Di RussoMadeleine M LoweryGiuseppe De VitoThe present work aimed at investigating the effects of mechanically amplified tremor on cortico-muscular coherence (CMC) in the alpha band. The study of CMC in this specific band is of particular interest because this coherence is usually absent in healthy individuals and it is an aberrant feature in patients affected by pathological tremors; understanding its mechanisms is therefore important. Thirteen healthy volunteers (23±4 years) performed elbow flexor sustained contractions both against a spring load and in isometric conditions at 20% of maximal voluntary isometric contraction (MVC). Spring stiffness was selected to induce instability in the stretch reflex servo loop. 64 EEG channels, surface EMG from the biceps brachii muscle and force were simultaneously recorded. Contractions against the spring resulted in greater fluctuations of the force signal and EMG amplitude compared to isometric conditions (p<.05). During isometric contractions CMC was systematically found in the beta band and sporadically observed in the alpha band. However, during the contractions against the spring load, CMC in the alpha band was observed in 12 out of 13 volunteers. Partial directed coherence (PDC) revealed an increased information flow in the EMG to EEG direction in the alpha band (p<.05). Therefore, coherence in the alpha band between the sensory-motor cortex and the biceps brachii muscle can be systematically induced in healthy individuals by mechanically amplifying tremor. The increased information flow in the EMG to EEG direction may reflect enhanced afferent activity from the muscle spindles. These results may contribute to the understanding of the presence of alpha band CMC in tremor related pathologies by suggesting that the origin of this phenomenon may not only be at cortical level but may also be affected by spinal circuit loops.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0115012&type=printable
spellingShingle Francesco Budini
Lara M McManus
Marika Berchicci
Federica Menotti
Andrea Macaluso
Francesco Di Russo
Madeleine M Lowery
Giuseppe De Vito
Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
PLoS ONE
title Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
title_full Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
title_fullStr Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
title_full_unstemmed Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
title_short Alpha band cortico-muscular coherence occurs in healthy individuals during mechanically-induced tremor.
title_sort alpha band cortico muscular coherence occurs in healthy individuals during mechanically induced tremor
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0115012&type=printable
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