TY - JOUR
T1 - Fundamental electrophysiologic investigation of spinal cord
T2 - Refractory period of feline conductive spinal cord evoked potential
AU - Ishikawa, Mami
AU - Yamaguchi, Noriyuki
AU - Bertalanffy, Helmut
AU - Tamura, Kiyotaka
AU - Ohira, Takayuki
AU - Takase, Moriichiro
AU - Kawase, Takeshi
PY - 1997/1/1
Y1 - 1997/1/1
N2 - 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.
AB - 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.
KW - Paired stimulus technique
KW - Recovery curve
KW - Refractory period
KW - Spinal cord evoked potential
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U2 - 10.1097/00004691-199707000-00006
DO - 10.1097/00004691-199707000-00006
M3 - Article
C2 - 9337143
AN - SCOPUS:0031401932
VL - 14
SP - 335
EP - 344
JO - Journal of Clinical Neurophysiology
JF - Journal of Clinical Neurophysiology
SN - 0736-0258
IS - 4
ER -