ALTERED CORTICOSPINAL TRANSMISSION TO THE HAND AFTER MAXIMUM VOLUNTARY EFFORTS

作者：Giesebrecht Sabine; Martin Peter G; Gandevia Simon C; Taylor Janet L^*

来源：Muscle & Nerve, 2011, 43(5): 679-687.

DOI：10.1002/mus.21938

• first dorsal interosseous
• corticospinal tract
• human
• motor cortex
• premotoneuronal synapse

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 cervico-medullary 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 similar to 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 similar to 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 43: 679-687, 2011

• 出版日期2011-5