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ID 637
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Topographical Analysis of the Hypnagogic EEG
creator
Tanaka, Hideki
Hori, Tadao
subject
EEG anterior-posterior index
EEG central-peripheral index
EEG topography
Hypnagogic state
NDC
Medical sciences
abstract
The present study examined the topographical characteristics for the typical nine EEG patterns during the hypnagogic state. Spectral analysis of the 12 scalp EEGs (F_<p1>, _<p2>, F_7,F_8,F_z, C_3,C_4,P_z, T_5,T_6,O_1 and O_2) was carried out on 10 male students (20-25yr). Topographic maps from consecutive samples of 30sec period for six frequency bands (delta : 2.0-3.8Hz, theta : 4.0-7.4Hz, alpha 1 : 7.6-9.4Hz, alpha 2 : 9.6-11.4Hz, alpha 3 : 11.6-13.4Hz, sigma : 13.0-14.8Hz) were studied from the light off to the stage 3 onset, which was scored by standard sleep stage criterion. Topographic maps demonstrated that the dominant areas of alpha band activities moved from the posterior area (P_z, T_5,T_6,O_1,O_2) to the anterior area (F_<p1>, F_<p2>, F_z, F_7,F_8) on the midline of scalp in association with the progress of hypnagogic EEG stages, which were scored by the criterion of Hori et al. (1991). On the other hand, the dominant area of delta, theta and sigma bands activities were on the central area (F_z, C_3,C_4,P_z) of scalp. The differences of EEG activities between the central and the peripheral areas (F_<p1>, F_<p2>, F_7,F_8,T_5,T_6,O_1,O_2) increased as a function of EEG stages. To describe the topographical characteristics of EEG stages quantitatively, the EEG anterior-posterior (A/P) indexes and the EEG central-peripheral (C/P) indexes were computed for each frequency band and for each stage. The A/P indexes in alpha band started to increase from stage 1 to stage 9 as a function of EEG stages. On the other hand, the sigma band C/P indexes did not increse in early stages, but started to increase rapidly after stage 7. These results show that the sigma C/P indexes are sensitive to detect the EEG changes in later process of hypnagogic state, especially to the vertex sharp wave and spindle activities. The results of this study suggest that the alpha band A/P index and the sigma band C/P index would be good objective indicators to describe the hypnagogic EEG activities.
journal title
Memoirs of the Faculty of Integrated Arts and Sciences, Hiroshima University. IV, Science reports
volume
Volume 19
start page
111
end page
122
date of issued
1993-12-31
publisher
広島大学総合科学部
contributor
国立情報学研究所
date of created
2006-03-21
issn
1340-8364
ncid
SelfDOI
language
jpn
nii type
Departmental Bulletin Paper
HU type
Departmental Bulletin Papers
DCMI type
text
format
application/pdf
text version
publisher
department
Graduate School of Integrated Arts and Sciences
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