| Project/Area Number |
09670640
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurology
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| Research Institution | UNIVERSITY OF TOKYO |
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Principal Investigator |
UGAWA Yoshikazu University of Tokyo, Department of Neurology, Associated Professor, 医学部・附属病院, 講師 (50168671)
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| Co-Investigator(Kenkyū-buntansha) |
HIKOSAKA Okihide Juntendo University First Department of Physiology, Professor, 医学部, 教授 (70120300)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | magnetic stimulation / fMRI / eye movement / motor cortex / basal ganglia / inhibition / interneurone / 小脳 |
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| Research Abstract |
A.Oculomotor control in humans
Our study on the effect of magnetic stimulation on the reaction time revealed that intersensory facilitation elicited by sound or sensory stimulus associated with magnetic stimulation has significant influence on the reaction times. This indicates that we have to mind the intersensory facilitation in the reaction time experiments using magnetic stimulation. We showed that the motor point determined by magnetic stimulation over the skull with a figure-8-shaped coil was positioned over the activated area in fMRI study, which implies that the activated cortical area by a figure-8-shaped coil is just under the center of a figure-8-shaped coil. Based on these findings, we studied cortical control of eye movement in the antisaccade task by magnetic stimulation with a figure-8-shaped coil. The posterioparietal cortex plays an important role mainly at 8Oms after the cue in the antisaccade which usually occurs at about 200ms after the cue, and the frontal eye field
… More
at lOOms.
B.Intracortical inhibition of the human motor cortex studied by a paired-palse stimulation
The effect of a subthreshold conditioning stimulus on MEPs to a succeeding suprathreshold test stimulus was considered to be produced by the intracortical inhibitory mechanisms probably mediated by GABA, which provides us refined movements. We revealed that this suppressive effect occurs mainly on 13-waves but not 11-waves by recording FDI muscles. Our studies of hand muscles in various neurological disorders demonstrated that this suppression was reduced or absent in patients with cortical myoclonus, dystonia, dyskinesia and Parkinson's disease, but not disturbed in patients with ataxia, chorea or sensory disturbances. This suggests that inputs from basal ganglia to motor cortex must have some influence on the intra-motor-cortical suppression system studied with this method, but inputs from the sensory cortex or cerebellum must have little or no influence. We also studied the sternocleidomastoid muscle (SCM) with the same paired-pulse stimulation method. This showed that the same inhibitory system as that of hand motor area is present in the neck motor area, and that this system is involved in patients with spasmodic torticollis which is a kind of dystonia. Less
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