Single muscle fiber discharge transformations: Fibrillation potential to positive sharp wave

Daniel Dumitru, John C King, Roger McCarter

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


It is presently believed that a fibrillation potential (FP) can transform into a positive sharp wave (PSW) by displaying a number of individual transitional potentials with a high degree of morphological variation between different sets of independent transformations. Clinically obtained examples of FP-to-PSW transformations and a myotonic discharge transformation are simulated by a finite fiber computer model. The simulations demonstrate that the two clinical FP-to-PSW examples may well be the result of two independent muscle fibers synchronously firing for a short period of time such that their separate waveforms summate at the electrode to create a false impression of one potential changing into another through a specific series of transitional waveforms. The transition characterized by the myotonic discharge is substantiated through modeling to define the most reasonable transitional series of waveform morphologies for a single muscle fiber. The combination of clinical examples, histological needle electrode muscle penetration studies, and simulations of single muscle fiber discharge transitions support the hypothesis that a needle recording electrode is capable of inducing a variable degree of mechanical compression with a commensurate amount of action potential blockade. The degree of action potential blockade directly contributes to the clinically observed configuration for the single muscle fiber discharge in both innervated and denervated tissues.

Original languageEnglish (US)
Pages (from-to)1759-1768
Number of pages10
JournalMuscle and Nerve
Issue number12
StatePublished - 1998
Externally publishedYes


  • Computer modeling
  • Fibrillation potential
  • Myotonic discharge
  • Needle electromyography
  • Positive sharp wave

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)
  • Cellular and Molecular Neuroscience
  • Physiology


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