Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Nonlinear behaviour of human motoneurons

L Smith1, T Zhong, P Bawa

  • 1School of Kinesiology, Simon Fraser University, Burnaby, BC, Canada.

Canadian Journal of Physiology and Pharmacology
|January 1, 1995
PubMed
Summary

Human motor unit activity during ramp-and-hold tasks shows nonlinear firing patterns. This contrasts with linear electromyographic (EMG) responses, suggesting recruitment explains overall muscle activation linearity.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Mapping of the ARIX homeodomain gene to mouse chromosome 7 and human chromosome 11q13.

Genomics·1996
Same author

Physician-patient relationships: patients as friends and patients who harass.

CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne·1996
Same author

Regulation of expression of sodium-calcium exchanger and plasma membrane calcium ATPase by protein kinases, glucocorticoids, and growth factors.

Annals of the New York Academy of Sciences·1996
Same author

GMSC's advice on intrapartum care is unhelpful.

BMJ (Clinical research ed.)·1996
Same author

Levels of soluble cell adhesion molecules in patients with dyslipidemia.

Circulation·1996
Same author

Vision, cognition and developmental characteristics of girls and women with Rett syndrome.

Developmental medicine and child neurology·1996

Area of Science:

  • Neuroscience
  • Motor Control
  • Human Physiology

Background:

  • Motoneuron firing rates exhibit dynamic and steady-state phases in response to injected currents.
  • In humans, motoneuron behavior is inferred from force parameters and gross electromyographic (EMG) activity.
  • Population EMG responses correlate linearly with force magnitude and rate of change.

Purpose of the Study:

  • To investigate the linearity of single motor unit firing patterns during dynamic and steady-state phases in humans.
  • To compare single motor unit activity with simultaneous EMG recordings during controlled force tasks.

Main Methods:

  • Simultaneous recording of single motor unit and EMG activities from the flexor carpi radialis muscle.
  • Human subjects performed ramp-and-hold force trajectories.
  • Analysis of motor unit firing patterns in relation to force parameters and background activity levels.

Main Results:

  • EMG activity demonstrated a linear relationship with the magnitude and rate of change of force.
  • Single motor unit firing patterns exhibited a nonlinear response to force parameters.
  • Motor unit recruitment was identified as the likely cause for the linear EMG behavior.

Conclusions:

  • Single motor unit responses to force tasks are nonlinear, challenging assumptions based on population EMG linearity.
  • Motor unit recruitment, rather than solely rate coding, underlies the observed linear EMG responses.
  • Further research is needed to fully elucidate the complex interplay of motor unit behavior in human force production.

Related Experiment Videos