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Altered corticospinal transmission to the hand after maximum voluntary efforts
Author(s) -
Giesebrecht Sabine,
Martin Peter G.,
Gandevia Simon C.,
Taylor Janet L.
Publication year - 2011
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.21938
Subject(s) - corticospinal tract , contraction (grammar) , stimulation , muscle contraction , anatomy , medicine , physical medicine and rehabilitation , magnetic resonance imaging , diffusion mri , radiology
Abstract Introduction: After maximal voluntary contractions (MVCs), responses to corticospinal tract stimulation change differently in arm and leg muscles. This study we examined responses in the first dorsal interosseous muscle (FDI). Methods: Stimulation of the corticospinal tract at the cervicomedullary motor evoked potentials in FDI. Stimuli were delivered before and after 10‐s and 1‐min MVCs. The reproducibility of changes in the cervicomedullary motor evoked potentials (CMEPs) was investigated. F‐waves tested motoneuron excitability. Results: After the MVCs, the CMEP area was initially variable. By ∽1 min after 10‐s and 1‐min MVCs, CMEPs in relaxed muscle decreased to 63 ± 15% and 52 ± 32%, respectively, of control and remained depressed for ∽10 min. Responses evoked 2 days apart varied between subjects but not between days. After 10‐s MVCs, F‐waves were reduced at rest. During weak contraction, CMEPs but not F‐waves were depressed. Conclusions: Our results suggest that contraction produces changes at the corticomotoneuronal synapses to FDI. In addition, motoneuron excitability is reduced. Muscle Nerve, 2011