1993 Fiscal Year Final Research Report Summary
Clinical and experimental study for establishment of epilepsy surgery in the MRI era.
| Project/Area Number |
04454361
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | Shimane Medical University |
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Principal Investigator |
MORITAKE Kouzo Shimane Medical University, Department of Neurosurgery, Professor, 医学部, 教授 (90093327)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Masatoshi Shimane Medical University, Department of Neurosurgery, Associate Professor, 医学部, 助教授 (90135567)
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| Project Period (FY) |
1992 – 1993
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| Keywords | intractable epilepsy / MRI / resective surgery / epileptogenic / experimental study / electroencephalography / intraoperative monitoring |
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| Research Abstract |
We schemed out a new protocol for surgical treatment of epilepsy in which MRI is the most reliable diagnostic tool for identifying lesions to be resected. When the lesion is diagnosed to be epileptogenic electrophysiologically and hemodynamically by presurgical evaluation, we perform craniotomy, identify the lesion revealed by MRI, and confirm its epileptogenicity. Resective surgery was undertaken in 42 cases. Their age at surgery ranges from 2 to 51 (mean 18) years, and duration of their seizure desorder was from one to 41 (mean 10). Dominant site of the brain resection was not temporal but extratemporal. Major pathological findings of resected specimens were gliotic and hamartomatous lesions. In both temporal and extratemporal resection groups, clinical outcome was excellent in about 60% of surgical causes and good in 30%. Postoperative permanent neurological deficit or complication was encountered in none of cases. The experiments were performed on tissue which was resected strictly for therapeutic reasons. Single neuronal activities were extracellulary recorded using glass microelectrodes. Since most neurons did not show spontaneous activities, orthodromic spikes were elecited using stimulating electrodes placed in the vicinity of recorded neurons. Two types of neurons, which showed different firing patterns, indicated different sensitivities to GABA.Type A neurons showed repetitive or burst firings following a local stimulation. The orthodromically activated firings of the type A neuron were inhibited by low concentrations ofGABA.Type B neurons showed only single firing even when a supramaximal stimulation was delivered, and their neuronal activities were inhibited only by high concentrations of GABA.These results suggest that, in chronic epileptic foci, neurons related with burst generation are more sensitive to GABA than those that displayd normal neuronal activities.
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