title: Human scalp recorded sigma activity is modulated by slow EEG oscillations during deep sleep.
abstract: The EEG during deep sleep exhibits a distinct cortically generated slow oscillation of around and below 1 Hz which can be distinguished from other delta (0.5-3.5 Hz) activity. Intracranial studies showed that this slow oscillation triggers and groups cortical network firing. In the present study, we examined whether the phases of the slow oscillation during sleep stage 4 are correlated with the magnitude of sigma (12-16 Hz) and gamma (> 20 Hz) scalp activity. For this purpose, 10-min segments of uninterrupted stage 4 sleep EEG from 9 subjects were analyzed by applying wavelet techniques. We found that scalp recorded sigma, but not gamma, activity is modulated by the phases of the slow oscillation during deep sleep. Enhancement of sigma activity was observed to be triggered by the peak of the surface positive slow wave component, whereas reduction of sigma activity started around the peak of the negative component.
authors.affiliation: Dept. of Epileptology, University of Bonn, Sigmund-Freud Str. 25, D-53105 Bonn, Germany. juergen.fell@ukb.uni-bonn.de
authors.forename: Jürgen
authors.initials: J
authors.lastname: Fell
authors.forename: Hakim
authors.initials: H
authors.lastname: Elfadil
authors.forename: Joachim
authors.initials: J
authors.lastname: Röschke
authors.forename: Wieland
authors.initials: W
authors.lastname: Burr
authors.forename: Peter
authors.initials: P
authors.lastname: Klaver
authors.forename: Christian E
authors.initials: CE
authors.lastname: Elger
authors.forename: Guillén
authors.initials: G
authors.lastname: Fernández
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D004569:Electroencephalography; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*