| Project/Area Number |
11670621
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
NAGAMINE Takashi Kyoto University, Department of Brain Pathophysiology, Associate Professor, 医学研究科, 助教授 (10231490)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Akio Kyoto University, Department of Neurology, Instructor, 医学研究科, 助手 (90212761)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | voluntary movement / self-paced movement / sustained muscle contraction / movement-related magnetic cortical field / coherence / electrocorticography / rhythmic activity / termination of movement / 反応性運動 / 運動終止 / 脳磁場 / 脱同期化 |
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| Research Abstract |
In order to investigate the contribution of the cerebral cortex to the control of voluntary movement, we analyzed rhythmic activity of the brain during and at the termination of the muscle contraction.
1. We recorded cortical magnetic field from five normal volunteers with whole-head magnetometer while they performed two kinds of movements. The first task was to make brisk phasic extension of the right index finger and the second one was to sustain isometric muscle contraction for 2 seconds following brisk extension. Initiation of the desynchronization of the background magnetic field was obserbed at 2 or 3 seconds prior to the movement onset for both 10 Hz and 20 Hz range. Desynchronization of the 10 Hz activity recovered within 1.5 seconds. On the other hand, desynchronization of the 20 Hz activity continued during the sustained muscle contraction and started to synchronize when contraction stopped.
2. We evaluated the interaction between cerebral magnetic field and muscle activity by
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coherence while subjects performed weak isometric muscle contraction of the unilateral hand or wrist. Coherence between the magnetic field corresponding motor cortex and electromyography showed common rhythmic activity at 15-20 Hz. Estimation from phase difference obtained by crosscorrelogram demonstrated that time lag between them was 15 ms, which corresponded to the transmission time along corticospinal tract.
3. We recorded coherence between electromyography and electrocorticogram of the epileptic patients while they performed isometric contraction during the period of long-term monitoring. Significant coherence around 15 Hz was obserbed at around 10 electrodes which were spaced 1 cm apart. Largest coherence was observed at the electrode demonstrating the largest response following electric stimuli.
We demonstrated that 10 Hz and 20 Hz rhythmic activity has different role for muscle contraction. 10 Hz is mainly contributing initiation of muscle contraction and 20 Hz is for maintenance of the sustained contraction. We also showed the relationship between cortex and muscle is significant at 15 Hz. Local rhythmic activity of the brain and association between cortex and muscle has different role for binding. Less
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