Effects of spinal cord ischemia on the refractory period of descending spinal cord evoked potential

Mami Ishikawa, Noriyuki Yamaguchi, Helmut Bertalanffy, Takayuki Oohira, Moriichiro Takase, Takeshi Kawase, Shigeo Toya

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Abstract

The recovery cycle, following the conduction of action potentials along a nerve fiber, consists of the absolute refractory period (ARP), the relative refractory period (RRP) and the supernormal period (SNP). The recovery cycle of the descending conductive spinal cord evoked potential (SCEP) was shown during normal state, ischemia and after ischemia using paired stimuli in cats. During ischemia the refractory period revealed a trend towards increment. Five minutes after reperfusion the refractory period decreased transiently compared with the normal level and within 30 min the refractory period returned to the normal level. The recovery curve of the 2nd potential showed different pattern compared with that of the 1st potential. Moreover, during ischemia, firstly the 3rd potential and secondly the 2nd potential of the SCEP elicited by the 2nd stimulus were disturbed. These results demonstrated that there is increased excitability of the spinal cord to the second stimulus after a brief period of ischemia, and that the 2nd and 3rd potentials are evoked synaptically and easily disturbed during ischemia. Measuring the SCEP elicited by paired stimuli or constructing the recovery curve of the SCEP is useful for the electrophysiological assessment of spinal cord function.

Original languageEnglish
Pages (from-to)54-63
Number of pages10
JournalElectroencephalography and Clinical Neurophysiology
Volume102
Issue number1
DOIs
Publication statusPublished - 1997 Jan

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Keywords

  • excitability
  • paired stimulation
  • recovery curve
  • spinal cord evoked potential
  • spinal cord ischemia

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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