title: Progression to deep sleep is characterized by changes to BOLD dynamics in sensory cortices.
abstract: Sleep has been shown to subtly disrupt the spatial organization of functional connectivity networks in the brain, but in a way that largely preserves the connectivity within sensory cortices. Here we evaluated the hypothesis that sleep does impact sensory cortices, but through alteration of activity dynamics. We therefore examined the impact of sleep on hemodynamics using a method for quantifying non-random, high frequency signatures of the blood-oxygen-level dependent (BOLD) signal (amplitude variance asymmetry; AVA). We found that sleep was associated with the elimination of these dynamics in a manner that is restricted to auditory, motor and visual cortices. This elimination was concurrent with increased variance of activity in these regions. Functional connectivity between regions showing AVA during wakefulness maintained a relatively consistent hierarchical structure during wakefulness and N1 and N2 sleep, despite a gradual reduction of connectivity strength as sleep progressed. Thus, sleep is related to elimination of high frequency non-random activity signatures in sensory cortices that are robust during wakefulness. The elimination of these AVA signatures conjointly with preservation of the structure of functional connectivity patterns may be linked to the need to suppress sensory inputs during sleep while still maintaining the capacity to react quickly to complex multimodal inputs.
authors.affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy.
authors.forename: Ben
authors.initials: B
authors.lastname: Davis
authors.affiliation: Department of Neurology and Brain Imaging Center, Goethe University, Frankfurt, Germany.
authors.forename: Enzo
authors.initials: E
authors.lastname: Tagliazucchi
authors.affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy.
authors.forename: Jorge
authors.initials: J
authors.lastname: Jovicich
authors.affiliation: Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany; Department of Neurology and Brain Imaging Center, Goethe University, Frankfurt, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Laufs
authors.affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy. Electronic address: uri.hasson@unitn.it.
authors.forename: Uri
authors.initials: U
authors.lastname: Hasson
mesh_terms: D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D012890:Sleep / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult