End-of-Fiber Signals Strongly Influence the First and Second Phases of the M Wave in the Vastus Lateralis: Implications for the Study of Muscle Excitability.
Fiche du document
2018
- doi: 10.3389/fphys.2018.00162
- issn: 1664-042X
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/doi/10.3389/fphys.2018.00162
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/pmid/29568271
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/pissn/1664-042X
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_B4AC89010A176
info:eu-repo/semantics/openAccess , CC BY 4.0 , https://creativecommons.org/licenses/by/4.0/
Sujets proches
Muscle Musculature Myodynamics MyologyCiter ce document
J. Rodriguez-Falces et al., « End-of-Fiber Signals Strongly Influence the First and Second Phases of the M Wave in the Vastus Lateralis: Implications for the Study of Muscle Excitability. », Serveur académique Lausannois, ID : 10.3389/fphys.2018.00162
Métriques
Partage / Export
Résumé
It has been recurrently observed that, for compound muscle action potentials (M wave) recorded over the innervation zone of the vastus lateralis , the descending portion of the first phase generally shows an "inflection" or "shoulder." We sought to clarify the electrical origin of this shoulder-like feature and examine its implications. M waves evoked by maximal single shocks to the femoral nerve were recorded in monopolar and bipolar configurations from 126 individuals using classical (10-mm recording diameter, 20-mm inter-electrode distance) electrodes and from eight individuals using small electrodes arranged in a linear array. The changes of the M-wave waveform at different positions along the muscle fibers' direction were examined. The shoulder was identified more frequently in monopolar (97%) than in bipolar (46%) M waves. The shoulder of M waves recorded at different distances from the innervation zone had the same latency. Furthermore, the shoulder of the M wave recorded over the innervation zone coincided in latency with the positive peak of that recorded beyond the muscle. The positive phase of the M wave detected 20 mm away from the innervation zone was essentially composed of non-propagating components. The shoulder-like feature in monopolar and bipolar M waves results from the termination of action potentials at the superficial aponeurosis of the vastus lateralis . We conclude that, only the amplitude of the first phase, and not the second, of M waves recorded monopolarly and/or bipolarly in close proximity to the innervation zone can be used reliably to monitor possible changes in muscle membrane excitability.