title: Topographic mapping of electroencephalography coherence in hypnagogic state.
abstract: The present study examined the topographic characteristics of hypnagogic electroencephalography (EEG), using topographic mapping of EEG power and coherence corresponding to nine EEG stages (Hori's hypnagogic EEG stages). EEG stages 1 and 2, the EEG stages 3-8, and the EEG stage 9 each correspond with standard sleep stage W, 1 and 2, respectively. The dominant topographic components of delta and theta activities increased clearly from the vertex sharp-wave stage (the EEG stages 6 and 7) in the anterior-central areas. The dominant topographic component of alpha 3 activities increased clearly from the EEG stage 9 in the anterior-central areas. The dominant topographic component of sigma activities increased clearly from the EEG stage 8 in the central-parietal area. These results suggested basic sleep process might start before the onset of sleep stage 2 or of the manually scored spindles.
authors.affiliation: Department of Behavioral Sciences, Faculty of Integrated Arts and Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Hori
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D003700:Delta Rhythm; D004325:Dreams / Q000502:physiology*; D004569:Electroencephalography; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted; D012894:Sleep Stages / Q000502:physiology*