Voluntary activation of muscle in humans

This work was completed during my MSc in the Exercise Neuroscience Laboratory of Dr. Jayne Kalmar at Wilfrid Laurier University in Waterloo, Ontario, Canada.

In this project, I studied plasticity in inhibitory circuits that act between hemispheres of the motor cortex circuits in humans. These circuits are believed to contribute to our ability to perform tasks with our hands independent of one another.

In some states or conditions, this capacity becomes impaired, leading the the emergence of involuntary mirror movements while performing tasks that are indented to be unimanual.

I studied plasticity in this circuit in three states:

  • Task-dependence
  • Neuromuscular Fatigue
  • Parkinson’s Disease

Tools

Electromyography

Transcranial Magnetic Stimulation

Outputs

Research Articles

Sharples, S.A., Gould J.A., Vandenberk, M.S., and Kalmar, J.M. (2016). Cortical mechanisms of neuromuscular fatigue and sense of effort. Plos ONE. 11 (2): e0149026. DOI: 10.1371/journal.pone.0149026.

Sharples, S.A., Almeida, Q.J., and Kalmar, J.M. (2014). Cortical mechanisms of mirror activation during maximal and submaximal finger contractions in Parkinson’s disease. Journal of Parkinson’s Disease.4, 437-452. DOI: 10.3233/JPD-130316.

Sharples, S.A. and Kalmar, J.M. (2012). Modulation of cortical excitability and interhemispheric inhibition prior to rhythmic unimanual contractions. Journal of Neuroscience Methods.210 (2): 178-186. DOI: 10.1016/j.neumeth.2012.07.08.

Selected Conference Abstracts

Sharples, S.A., Almeida, Q.J. and Kalmar, J.M. Cortical mechanisms of mirror activation in Parkinson’s disease. Canadian Neuroscience, Toronto, ON, May 2013

Sharples, S.A., Gould, J.A., Vandenberk, M.S., and Kalmar, J.M. Cortical mechanisms of supraspinal fatigue and sense of effort. Society for Neuroscience, New Orleans, Louisiana, USA, November 2012.

Sharples, S.A., and Kalmar, J.M. Modulation of cortical excitability and inhibition prior to a voluntary unimanual contraction. Society for Neuroscience, Washington D.C., November 2011.

Sharples, S.A., Almeida, Q.J., and Kalmar, J.M. The role of the supplementary motor area in interhemispheric and intracortical inhibition within the human motor cortex. Society for Neuroscience, San Diego, CA, November 2010.

Funding

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