title: Hemodynamic traveling waves in human visual cortex.
abstract: Functional MRI (fMRI) experiments rely on precise characterization of the blood oxygen level dependent (BOLD) signal. As the spatial resolution of fMRI reaches the sub-millimeter range, the need for quantitative modelling of spatiotemporal properties of this hemodynamic signal has become pressing. Here, we find that a detailed physiologically-based model of spatiotemporal BOLD responses predicts traveling waves with velocities and spatial ranges in empirically observable ranges. Two measurable parameters, related to physiology, characterize these waves: wave velocity and damping rate. To test these predictions, high-resolution fMRI data are acquired from subjects viewing discrete visual stimuli. Predictions and experiment show strong agreement, in particular confirming BOLD waves propagating for at least 5-10 mm across the cortical surface at speeds of 2-12 mm s-1. These observations enable fundamentally new approaches to fMRI analysis, crucial for fMRI data acquired at high spatial resolution.
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia. aquino@physics.usyd.edu.au
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Aquino
authors.forename: Mark M
authors.initials: MM
authors.lastname: Schira
authors.forename: P A
authors.initials: PA
authors.lastname: Robinson
authors.forename: Peter M
authors.initials: PM
authors.lastname: Drysdale
authors.forename: Michael
authors.initials: M
authors.lastname: Breakspear
mesh_terms: D001683:Biological Clocks / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003198:Computer Simulation; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008955:Models, Cardiovascular; D008959:Models, Neurological; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*