1988 Fiscal Year Final Research Report Summary
Physical Investigation of Human Brain Activities by EEG Spectrum Analysis
| Project/Area Number |
62540267
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般（含極低温･固体物性に対する理論）
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| Research Institution | Kyushu University |
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Principal Investigator |
AOKI Ryozo Department of Physics, Kyushu University, 理学部, 教授 (70037175)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Hazime Department of Physics, Kyushu University, 理学部, 教授 (90037143)
UENO Shyogo Department of Electronics, Kyushu University, 工学部, 教授 (00037988)
KATO Motohiro Department of Neurophisiology, Kyushu University, 医学部, 教授 (90038638)
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| Project Period (FY) |
1987 – 1988
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| Keywords | EEG / -wave mode / Frequency-spectrum Analysis / Photic driving effect / Photic flicker stimulation / カオス次元解析 / モード引き込み効果 |
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| Research Abstract |
In order to get insight into complicated but some systematical behavior of the human brain, spectrum analysis of EEG (electro-encephalogram) has been carriedout, and the following results could be obtained.
the EEG spectrum shows proper -mode peak ( =8- 12 H_z) at the eyes-closed rest state. Under photic flicker stimulation, an enforced synchronous oscillation appeares on EEG and the corresponding _<ex> peak is induced on the EEG frequency spectrum.
When _<ex> approaches to , characteristic interference effect takes place, depending on the _<ex> mode strength and the distance | _<ex>- |. Here observed is an interesting fact that this interference is also strongly characterized by the proper-mode personality.
when the -mode forms a sharp single spectrum peak, this mode is rigid (type I) and only disturbed by strong external stimulation, and brings peak spectrum degradation. In alternatives, the -mode is rather flexible (type II) and is expressed by small multi-peaks spectra. This mode is easily modified by the external stimulation _<ex> and concentrated in a single peak at _<ex> on frequency spectrum.
These mode-spectrum changes have been also found reflected on the portrait of the phase trajectory in chaotic dynamics. In case of type i, the intrinsic attractor structure in the portrait is dispersed by the stimulation. In contrast, for the type II case we could find some time rearrangement of the trajectory distribution into an expanding torus-like pattern.
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Research Products
(10 results)
