Multiple action potential waveforms of single units in man as signs of variability in conductivity of their myelinated fibres

Gang Wu, Rolf G. Hallin, Rolf Ekedahl

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Percutaneous microneurography was performed with concentric needle electrodes to record neural activity from myelinated fibres in human peripheral nerves. Template matching techniques were used together with interspike interval analysis and studies on functional class, receptive field characteristics, conduction velocities and other single fibre properties to classify single units. Sometimes the same fibres exhibited different action potentials at the same time. The potentials had some common features, but differed either in their waveform types or only in duration. There was a correlation between the occurrence of the different potential shapes and firing frequency of the studied unit. The outcome of the studies suggested that there was a common denominator which could explain the observations. Most likely, momentary fluctuations in excitability of the myelinated fibres occurring during the relative refractory period or the supernormal period were responsible for the variations in complexity of the studied units due to a partial block of fibre propagation probably caused by the recording electrode. Thus, action potentials deriving from the same axon may not always have the same shapes. Methods for unit classification, such as template matching, are discussed in the light of our findings.

Original languageEnglish (US)
Pages (from-to)225-238
Number of pages14
JournalBrain research
Issue number1-2
StatePublished - Dec 2 1996
Externally publishedYes


  • action potential shape
  • concentric needle electrode
  • human peripheral nerve
  • microneurography
  • propagation block
  • single unit recording
  • template matching

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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