Excitatory synaptic potentials in spastic human motoneurons have a short rise-time

Nina L. Suresh*, Michael D. Ellis, Jennifer Moore, Heather Heckman, William Zev Rymer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


This study assessed whether changes in size or time-course of excitatory postsynaptic potentials (EPSPs) in motoneurons innervating spastic muscle could induce a greater synaptic response, and thereby contribute to reflex hyperexcitability. We compared motor unit (MU) firing patterns elicited by tendon taps applied to both spastic and contralateral (nonspastic) biceps brachii muscle in hemiparetic stroke subjects. Based on recordings of 115 MUs, significantly shortened EPSP rise times were present on the spastic side, but with no significant differences in estimated EPSP amplitude. These changes may contribute to hyperexcitable reflex responses at short latency, but the EPSP amplitude changes appear insufficient to account for global differences in reflex excitability.

Original languageEnglish (US)
Pages (from-to)99-103
Number of pages5
JournalMuscle and Nerve
Issue number1
StatePublished - Jul 2005


  • Excitatory postsynaptic potential
  • Hemiparetic stroke
  • Peristimulus time histogram
  • Single motor units
  • Spasticity

ASJC Scopus subject areas

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


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