Fundamental electrophysiologic investigation of spinal cord: Refractory period of feline conductive spinal cord evoked potential

Mami Ishikawa, Noriyuki Yamaguchi, Helmut Bertalanffy, Kiyotaka Tamura, Takayuki Ohira, Moriichiro Takase, Takeshi Kawase

Research output: Contribution to journalArticle

2 Citations (Scopus)


Refractory periods and recovery curves have been used to investigate the physiologic importance and disturbance of peripheral nerves, but the refractory periods of the central nervous system (CNS) have seldom been investigated. We estimated the refractory periods and the recovery curves of the ascending and descending conductive spinal cord evoked potentials (SCEP) in cats. The absolute refractory period of the first and second potentials of both the ascending and descending SCEP was ~0.4-0.5 ms. The amplitudes of the first potentials of the ascending and descending SCEP elicited by test stimuli exhibited significant differences, but their latencies did not differ significantly except at the interstimulus interval (ISI) of 1.5 ms, which implies that the same type of fibers was stimulated in the first potentials of the ascending and descending SCEP. The second potential of the descending SCEP elicited by test stimulus showed > 100% amplitude and a maximal recovery of 200% when the ISI was 3.0 ms. The third potential was produced in the test response more easily when a lower vertebral level (LA) was used as the recording site and the ISI was between 1.0 and 4.0 ms. We consider these phenomena to be the result of elimination of the synaptic inhibitory influence by the conditioning stimulus of the paired stimuli for the descending SCEP.

Original languageEnglish
Pages (from-to)335-344
Number of pages10
JournalJournal of Clinical Neurophysiology
Issue number4
Publication statusPublished - 1997 Jan 1



  • Paired stimulus technique
  • Recovery curve
  • Refractory period
  • Spinal cord evoked potential

ASJC Scopus subject areas

  • Physiology
  • Neurology
  • Clinical Neurology
  • Physiology (medical)

Cite this