Introduction: The relationship between output force and motor command depends on the intrinsic dynamic responses of motor units (MUs), which can be characterized by evoking accurate sinusoidal force responses at different frequencies. In this study we sought to determine whether sinusoidal modulation of the stimulation rate of single MUs results in reliable sinusoidal force changes.
Methods: Single axons of rat ventral roots were stimulated electrically by changing the pulse rate sinusoidally at different frequency modulation (0.4-1.0-2.0-4.0 Hz for slow, 1.0-2.0-4.0-7.0 Hz for fast MUs). The twitching sinusoidal force signal was interpolated. We calculated harmonic distortion (HD) and the correlation coefficient (r) between theoretical sines and interpolated signals.
Results: HD was always <5%, and r was always >0.97.
Conclusions: The HD and r-values obtained indicate highly reliable sinusoidal responses, which supports the potential use of this method to further characterize the dynamic behavior of single MUs.
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http://dx.doi.org/10.1002/mus.24464 | DOI Listing |
J Appl Physiol (1985)
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Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland.
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Liver metastasis is the main cause of cancer-related mortality. During the metastasis process, circulating carcinoma cells hardly pass through narrow capillaries, leading to nuclear deformation. However, the effects of nuclear deformation and its underlying mechanisms on metastasis need further study.
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School of Mathematics and Statistics, The University of Melbourne, Parkville, Australia.
The epidemiological behavior of Plasmodium vivax malaria occurs across spatial scales including within-host, population, and metapopulation levels. On the within-host scale, P. vivax sporozoites inoculated in a host may form latent hypnozoites, the activation of which drives secondary infections and accounts for a large proportion of P.
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