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Temporal evolution of coherence and power in the human sleep electroencephalogram
Author(s) -
Achermann Peter,
BorbÉly Alexander
Publication year - 1998
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1046/j.1365-2869.7.s1.6.x
Subject(s) - coherence (philosophical gambling strategy) , electroencephalography , sleep (system call) , psychology , neuroscience , cognitive psychology , computer science , mathematics , statistics , operating system
Coherence analysis of the human sleep electroencephalogram (EEG) was used to investigate relations between brain regions. In all‐night EEG recordings from eight young subjects, the temporal evolution of power and coherence spectra within and between cerebral hemispheres was investigated from bipolar derivations along the antero‐posterior axis. Distinct peaks in the power and coherence spectra were present in NREM sleep but not in REM sleep. They were situated in the frequency range of sleep spindles (13–14 Hz), alpha band (9–10 Hz) and low delta band (1–2 Hz). Whereas the peaks coincided in the power and coherence spectra, a dissociation of their temporal evolution was observed. In the low delta band, only power but not coherence showed a decline across successive NREM sleep episodes. Moreover, power increased gradually in the first part of a NREM sleep episode, whereas coherence showed a rapid rise. The results indicate that the intrahemispheric and interhemispheric coherence of EEG activity attains readily a high level in NREM sleep and is largely independent of the signal amplitude.