Topographic mapping of electroencephalography coherence in hypnagogic state
Hideki Tanaka, Mitsuo Hayashi, Tadao Hori
Psychiatry and Clinical Neurosciences April 1, 1998 DOI: 10.1111/j.1440-1819.1998.tb00998.x (opens in new tab)
Summary
AI-generated from the abstractHypnagogic EEG stages, defined by Hori's nine-stage system, show distinct topographic patterns of brain activity as sleep progresses. Delta and theta power increase prominently in anterior-central areas starting from the vertex sharp-wave stage (stages 6 and 7). Alpha 3 power increases in anterior-central areas from stage 9, and sigma power increases in the central-parietal area from stage 8. These findings suggest that basic sleep processes may begin before the onset of sleep stage 2 or before manually scored sleep spindles appear.
Study at a glance
| Characteristics | Observational study Peer reviewed |
|---|---|
| Key finding | Basic sleep processes may begin before the onset of sleep stage 2 or manually scored spindles, as indicated by increased delta, theta, alpha 3, and sigma activities in specific brain areas during hypnagogic EEG stages. |
Abstract
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.