High frequency waking EEG: reflection of a slow ultradian rhythm in daytime arousal.
The ultradian dynamics of the human waking EEG was studied using a short visual fixation task repeated every 10 min throughout the daytime. The EEG spectra obtained from the tasks were assessed for time effect and ultradian periodicity. Fronto-central EEG high frequency powers (22.5-44.5 Hz) decreased at the time of the midafternoon vigilance dip (14.00-17.00 h) along with slight concomitant increases in parietal alpha (7.5-13.5 Hz) and delta (1-3 Hz) powers. A slow ultradian rhythm with a 3-4 h periodicity strongly modulated EEG power in all frequency bands between 1 and 44.5 Hz. The high frequency waking EEG may well reflect the activity of a brain arousal process underlying maintenance of the waking state probably throughout the 24 h cycle.
Laboratoire des Régulations Physiologiques et des Rythmes Biologiques chez l'Homme, Institut de Physiologie, Faculté de Médecine, ULP, Strasbourg, France.
F
F
Chapotot
C
C
Jouny
A
A
Muzet
A
A
Buguet
G
G
Brandenberger
D000204:Activity Cycles / Q000502:physiology*; D000328:Adult; D000513:Alpha Rhythm; D001143:Arousal / Q000502:physiology*; D016477:Artifacts; D001683:Biological Clocks; D002540:Cerebral Cortex / Q000502:physiology*; D003700:Delta Rhythm; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005403:Fixation, Ocular; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000502:physiology; D014851:Wakefulness / Q000502:physiology*