Localization of auditory and somatosensory evoked field by magnetoencephalography
| Project/Area Number |
05404074
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Laboratory medicine
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| Research Institution | University of Tokyo |
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Principal Investigator |
YOTSUMOTO Hideki Univ.of Tokyo Hospital, assist Prof., 医学部(病), 講師 (10134545)
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| Co-Investigator(Kenkyū-buntansha) |
YUMOTO Masato Univ.of Tokyo Hospital, assistant, 医学部(病), 助手 (30240170)
UGAWA Yoshikazu Univ.of Tokyo Hospital, assistant., 医学部(病), 助手 (50168671)
HIRAMATSU Ken-ichi Univ.of Tokyo Hospital, assistant., 医学部(病), 助手 (50218814)
OOKUBO Akiyuki Univ.of Tokyo Hospital, ex Prof., 医学部(病), 教授 (20010423)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥13,800,000 (Direct Cost: ¥13,800,000)
Fiscal Year 1994: ¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1993: ¥10,100,000 (Direct Cost: ¥10,100,000)
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| Keywords | magnetoencephalography (MEG) / somatosensory evoked field (SEF) / auditory evoked field (AEF) / superconducting quantum interference device (SQUID) / 生体磁気 / 大脳聴覚野 / SQUID |
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| Research Abstract |
We investigated localization of somatosensory field by using a 37 channel first-order gradiometer magnetoencephalography.
Localiztion of somatosensory evoked magentic fields was studied by stimulating median nerve, and nerves distributing to thumb, digits, and small finger. Somatosensory evoked P22 magnetic fields was also investigated in ten normal volunteers. The median nerve was stimulated at the wrist, and evoked responses were recorded over the contralateral hemisphere. Half of the subjects showed a clearly identifiable magnetic counterpart (P22m) of the somatosensory evoked P22 component. A two dipole algorithm was applied to localize the generator of P22m which must coexist with a dipole for N20m-P30m at around the same latencies.
In three subjects, P22m was clearly localized to area 4 as an antiparallel current dipole closely adjacent to a N20m-P30m dipole on area 3b with the dipole moment of approximately a quarter of the latter.
We also investigated somatosensory evoked magnetic fields (SEFs) and somatosensory evoked potentials (SEPs) in patients with myoclonus epilepsy. The median nerve was stimulated at the wrist, and responses were recorded over the contralateral hemisphere. The source of the enlarged cortical component of the giant SEF was localized on the postcentral sensory cortex. The P1 component of the giant cortical response was composed mainly of a tangentially oriented dipole at area 3b. This is the first magnetoencephalographic analysis of an abnormally enlarged somatosensory cortical response.
The study indicates that magnetic responese in combination with electroencephalographic responses will enable us to estimate more acurate positioning of sources of somatosensory cortical responses.
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Report
(3 results)
Research Products
(10 results)
