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Regional differences in the circadian modulation of human sleep spindle characteristics
Author(s) -
Knoblauch Vera,
Martens Wim,
WirzJustice Anna,
Kräuchi Kurt,
Cajochen Christian
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2003.02729.x
Subject(s) - sleep spindle , circadian rhythm , frequency domain , sleep (system call) , neuroscience , electroencephalography , non rapid eye movement sleep , physics , biology , psychology , mathematics , computer science , operating system , mathematical analysis
Electroencephalographic oscillations in the sleep spindle frequency range (11–16 Hz) are a key element of human nonrapid eye movement sleep. In the present study, sleep spindle characteristics along the anterior–posterior axis were analysed during and outside the circadian phase of melatonin secretion. Sleep electroencephalograms were recorded during naps distributed over the entire circadian cycle and analysed with two different methodological approaches, the classical fast Fourier transform in the frequency‐domain and a new method for instantaneous spectral analysis, the fast time frequency transform that yields high‐resolution parameters in the combined time‐frequency‐domain. During the phase of melatonin secretion, spindle density was generally increased and intraspindle frequency variation reduced. Furthermore, lower spindle frequencies were promoted: peak frequencies shifted towards the lower end of the spindle frequency range, and spindle amplitude was enhanced in the low‐frequency range (11–14.25 Hz) and reduced in the high‐frequency range (∼14.5–16 Hz). The circadian variation showed a clear dependence on brain topography such that it was maximal in the parietal and minimal in the frontal derivation. Our data provide evidence that the circadian pacemaker actively promotes low‐frequency sleep spindles during the biological night with a parietal predominance.