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Electrical Stimulation of the Human Descending Motor Tracts at Several Levels

Published online by Cambridge University Press:  18 September 2015

Yoshikazu Ugawa ,
Kieko Genba-Shimizu  and
Ichiro Kanazawa
Yoshikazu Ugawa*
Affiliation:
Department of Neurology, Institute for Brain Research, School of Medicine, University of Tokyo, Tokyo
Kieko Genba-Shimizu
Affiliation:
Department of Neurology, Institute for Brain Research, School of Medicine, University of Tokyo, Tokyo
Ichiro Kanazawa
Affiliation:
Department of Neurology, Institute for Brain Research, School of Medicine, University of Tokyo, Tokyo
*
Department of Neurology, Institute for Brain Research, School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113, Japan
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Abstract:

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The descending motor tracts were activated using a high voltage electrical stimulation technique at four levels: the motor cortex, brainstem (around the pyramidal decussation), and the first and sixth thoracic vertebral levels (Tl, T6). Electromyographic activity was recorded from the tibialis anterior or extensor digitorum brevis muscles. Consistent motor action potentials could be evoked in all normal subjects. The conduction velocity of the descending tracts was estimated to be 62 to 79 m/s. The sum of synaptic delay and utilization time at the motoneurons (spinal delay time) was estimated to be 0.5 ± 0.3 ms indicating a mono- or oligosynaptic connection. In patients with diffusely affected descending tracts, the technique showed slowed conduction along the descending tracts and prolonged spinal delay time which may include the time required for temporal summation of excitatory postsynaptic potentials as well as synaptic delay and utilization time. In patients with a localized lesion, localized conduction delay was found at the appropriate segment.

Type
Original Articles
Information
Canadian Journal of Neurological Sciences , Volume 22 , Issue 1 , February 1995 , pp. 36 - 42
Copyright
Copyright © Canadian Neurological Sciences Federation 1995

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