title: Tracking brain arousal fluctuations with fMRI.
abstract: Changes in brain activity accompanying shifts in vigilance and arousal can interfere with the study of other intrinsic and task-evoked characteristics of brain function. However, the difficulty of tracking and modeling the arousal state during functional MRI (fMRI) typically precludes the assessment of arousal-dependent influences on fMRI signals. Here we combine fMRI, electrophysiology, and the monitoring of eyelid behavior to demonstrate an approach for tracking continuous variations in arousal level from fMRI data. We first characterize the spatial distribution of fMRI signal fluctuations that track a measure of behavioral arousal; taking this pattern as a template, and using the local field potential as a simultaneous and independent measure of cortical activity, we observe that the time-varying expression level of this template in fMRI data provides a close approximation of electrophysiological arousal. We discuss the potential benefit of these findings for increasing the sensitivity of fMRI as a cognitive and clinical biomarker.
authors.affiliation: Advanced Magnetic Resonance Imaging Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892; catie.chang@nih.gov.
authors.forename: Catie
authors.initials: C
authors.lastname: Chang
authors.affiliation: Section on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892; Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, and National Eye Institute, National Institutes of Health, Bethesda, MD 20892;
authors.forename: David A
authors.initials: DA
authors.lastname: Leopold
authors.affiliation: Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt am Main, Germany;
authors.forename: Marieke Louise
authors.initials: ML
authors.lastname: Schölvinck
authors.affiliation: Advanced Magnetic Resonance Imaging Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Hendrik
authors.initials: H
authors.lastname: Mandelkow
authors.affiliation: Advanced Magnetic Resonance Imaging Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Dante
authors.initials: D
authors.lastname: Picchioni
authors.affiliation: Advanced Magnetic Resonance Imaging Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, and National Eye Institute, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Frank Q
authors.initials: FQ
authors.lastname: Ye
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Janita N
authors.initials: JN
authors.lastname: Turchi
authors.affiliation: Advanced Magnetic Resonance Imaging Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892;
authors.forename: Jeff H
authors.initials: JH
authors.lastname: Duyn
mesh_terms: D000818:Animals; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D058256:Brain Waves / Q000502:physiology*; D008251:Macaca; D008279:Magnetic Resonance Imaging; D011859:Radiography; D009435:Synaptic Transmission / Q000502:physiology*
keywords: arousal; electrophysiology; resting-state fMRI; spontaneous fluctuations