title: Monochromatic ultra-slow (~0.1 Hz) oscillations in the human electroencephalogram and their relation to hemodynamics.
abstract: Previous studies demonstrated the presence of Monochromatic Ultra-Slow Oscillations (MUSO) in human EEG. In the present study we explored the biological origin of MUSO by simultaneous recordings of EEG, Near-Infrared Spectroscopy (NIRS), arterial blood pressure, respiration and Laser Doppler flowmetry. We used a head-up tilt test in order to check whether MUSO might relate to Mayer waves in arterial blood pressure, known to be enhanced by the tilting procedure. MUSO were detected in 8 out of 10 subjects during rest and showed a striking monochromatic spectrum (0.07-0.14 Hz). The spatial topography of MUSO was complex, showing multiple foci variable across subjects. While the head-up tilt test increased the relative power of Mayer waves, it had no effect on MUSO. On the other hand, the relative spectral power of 0.1 Hz oscillations in EEG, NIRS and blood pressure signals were positively correlated across subjects in the tilted condition. Eight subjects showed a coherence between MUSO and NIRS/arterial blood pressure. Moreover, MUSO at different electrode sites demonstrated coherence not reducible to volume conduction, thus indicating that MUSO are unlikely to be generated by one source. We related our experimental findings to known biological phenomena being generated at about 0.1 Hz, i.e.: arterial blood pressure, cerebral and skin vasomotion, respiration and neuronal activity. While no definite conclusion can yet be drawn as to an exact physiological mechanism of MUSO, we suggest that these oscillations might be of a rather extraneuronal origin reflecting cerebral vasomotion.
authors.affiliation: Neurophysics Group, Department of Neurology, Campus Benjamin Franklin, Charité, University Medicine, Hindenburgdamm 30, 12203 Berlin, Germany; Bernstein Center for Computational Neuroscience, Philippstraße 12, 10115 Berlin, Germany. Electronic address: vadim.nikulin@charite.de.
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Nikulin
authors.affiliation: Neurophysics Group, Department of Neurology, Campus Benjamin Franklin, Charité, University Medicine, Hindenburgdamm 30, 12203 Berlin, Germany.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Fedele
authors.affiliation: Berlin NeuroImaging Center, University Hospital Charité, Charitéplatz 1, 10117 Berlin, Germany; Machine Learning Group, Berlin Institute of Technology, Marchstrasse 23,10587 Berlin, Germany; Department of Neurology, Max Planck for Human Cognitive andBrain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Mehnert
authors.affiliation: Department of Neurology, Virchow Klinikum, University Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Lipp
authors.affiliation: Department of Neurology, Virchow Klinikum, University Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Noack
authors.affiliation: Berlin NeuroImaging Center, University Hospital Charité, Charitéplatz 1, 10117 Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Steinbrink
authors.affiliation: Neurophysics Group, Department of Neurology, Campus Benjamin Franklin, Charité, University Medicine, Hindenburgdamm 30, 12203 Berlin, Germany; Bernstein Center for Computational Neuroscience, Philippstraße 12, 10115 Berlin, Germany.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Curio
mesh_terms: D000328:Adult; D062186:Arterial Pressure; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004569:Electroencephalography; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D015656:Respiratory Mechanics / Q000502:physiology; D019265:Spectroscopy, Near-Infrared
keywords: Brain hemodynamics; EEG; NIRS; Neuronal oscillations