title: Regional Patterns of Cortical Phase Synchrony in the Resting State.
abstract: Synchronized phase estimates between oscillating neuronal signals at the macroscale level reflect coordinated activities between neuronal assemblies. Recent electrophysiological evidence suggests the presence of significant spontaneous phase synchrony within the resting state. The purpose of this study was to investigate phase synchrony, including directional interactions, in resting state subdural electrocorticographic recordings to better characterize patterns of regional phase interactions across the lateral cortical surface during the resting state. We estimated spontaneous phase locking value (PLV) as a measure of functional connectivity, and phase slope index (PSI) as a measure of pseudo-causal phase interactions, across a broad range of canonical frequency bands and the modulation of the amplitude envelope of high gamma (amHG), a band that is believed to best reflect the physiological processes giving rise to the functional magnetic resonance imaging BOLD signal. Long-distance interactions had higher PLVs in slower frequencies (≤theta) than in higher ones (≥beta) with amHG behaving more like slow frequencies, and a general trend of increasing frequency band of significant PLVs when moving across the lateral surface along an anterior-posterior axis. Moreover, there was a strong trend of frontal-to-parietal directional phase synchronization, measured by PSI across multiple frequencies. These findings, which are likely indicative of coordinated and structured spontaneous cortical interactions, are important in the study of time scales and directional nature of resting state functional connectivity, and may ultimately contribute to a better understanding of how spontaneous synchrony is linked to variation in regional architecture across the lateral cortical surface.
authors.affiliation: 1 Graduate Program in Neuroscience, University of Washington , Seattle, Washington.
authors.forename: Kaitlyn
authors.initials: K
authors.lastname: Casimo
authors.affiliation: 2 Department of Neurological Surgery, University of Washington , Seattle, Washington.
authors.forename: Felix
authors.initials: F
authors.lastname: Darvas
authors.affiliation: 3 Department of Bioengineering, University of Washington , Seattle, Washington.
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Wander
authors.affiliation: 2 Department of Neurological Surgery, University of Washington , Seattle, Washington.|4 Department of Neurosurgery, Harborview Medical Center , UW Medicine, Seattle, Washington.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ko
authors.affiliation: 5 Department of Radiology, University of Washington , Seattle, Washington.|6 Department of Neurology, University of Washington , Seattle, Washington.|7 Integrated Brain Imaging Center, UW Radiology , Seattle, Washington.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Grabowski
authors.affiliation: 8 Department of Neurology, Center for Integrated Brain Research, Seattle Children's Hospital , Seattle, Washington.
authors.forename: Edward
authors.initials: E
authors.lastname: Novotny
authors.affiliation: 9 Department of Radiology, Center for Clinical and Translational Research, Seattle Children's Hospital , Seattle, Washington.
authors.forename: Andrew
authors.initials: A
authors.lastname: Poliakov
authors.affiliation: 1 Graduate Program in Neuroscience, University of Washington , Seattle, Washington.|2 Department of Neurological Surgery, University of Washington , Seattle, Washington.|4 Department of Neurosurgery, Harborview Medical Center , UW Medicine, Seattle, Washington.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Ojemann
authors.affiliation: 1 Graduate Program in Neuroscience, University of Washington , Seattle, Washington.|5 Department of Radiology, University of Washington , Seattle, Washington.|7 Integrated Brain Imaging Center, UW Radiology , Seattle, Washington.
authors.forename: Kurt E
authors.initials: KE
authors.lastname: Weaver
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D058256:Brain Waves; D002540:Cerebral Cortex / Q000502:physiology*; D002648:Child; D003344:Cortical Synchronization; D000069280:Electrocorticography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D055815:Young Adult
keywords: functional connectivity; phase flow; phase locking; phase synchrony; resting state