1996 Fiscal Year Final Research Report Summary
Trial manufacture of high freguency repetitive magnetic stimuletor : stability, safety and clinical usefulness
| Project/Area Number |
06558109
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
Neuroscience in general
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KIMURA Jun Kyoto University, Medical School, Professor, 医学研究科, 教授 (10204976)
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| Co-Investigator(Kenkyū-buntansha) |
YARITA Masaru Nihon Koden Tomioka Corporation, Head Investigator, 第一技術部, 主任研究員
FUKUYAMA Hidenao Kyoto University, Medical School, Associate Professor, 医学研究科, 助教授 (90181297)
SHIBASAKI Hiroshi Kyoto University, Medical School, Professor, 医学研究科, 教授 (30037444)
AKIGUCHI Ichiro Kyoto University, Medical School, Associate Professor, 医学研究科, 助教授 (30115779)
KAJI Ryuji Kyoto University, Medical School, Lecturer, 医学研究科, 講師 (00214304)
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| Project Period (FY) |
1994 – 1996
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| Keywords | Magnetic stimulation / Repetitive stimulator / high freguency stimulator / safety / animal study / EMG / MEP / monkey |
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| Research Abstract |
Although there were many technical difficulties in developing the stimulators, we finally completed to manufacture a new stable high frequency repetitive magnetic stimulator. The stimulator operates from a standard 100V AC supply. Two types of magnetic stimulus pulses, induced by alternating capacitor voltage, were available : 1) a monophasic pulse with a rise time of 65 microseconds for single stimuli or paired stimuli and 2) a biphasic pulse with pulse width of 260 microseconds for single stimuli or repetitive stimuli. The maximum magnetic field gradient induced is 15.4T/sec.The maximum repetition rate is 20 Hz at 100% of maximal output and 30 Hz at 80%. Coil temperature is always monitored and if the temperature rises too high, the stimulator stops automatically. The stimulator worked without major troubles through the experiments.
In order to clarify the effect of the repetitive brain stimulation on the primates, compound muscle action potentials (CMAPs) evoked by repetitive transcranial magnetic stimulation were recorded from the forearm muscles in a Japanese monkey. All experiments were also recorded on a videotape. Stimulus intensity and rate were varied from 50% to 100% and from 1 Hz to 30 Hz respectively. The number of stimuli in a train was 20 and 99.
The results were as follows : 1) In general, high frequency repetitive stimuli augmented CMAP amplitude, suggesting increased excitability of corticospinal pathway. 2) However, in 10 Hz stimuli, CMAP were sometimes diminished, possibly due to frequency dependent cortical suppression in the brain. 3) No seizure occurred during the experiments. 4) No obvious side effect after the experiments.
In our experiments, the repetitive brain stimulation was carried out without any trouble, but further studies are needed to establish the safety and usefulness of this new method.
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Research Products
(10 results)
