title: Shock-like haemodynamic responses induced in the primary visual cortex by moving visual stimuli.
abstract: It is shown that recently discovered haemodynamic waves can form shock-like fronts when driven by stimuli that excite the cortex in a patch that moves faster than the haemodynamic wave velocity. If stimuli are chosen in order to induce shock-like behaviour, the resulting blood oxygen level-dependent (BOLD) response is enhanced, thereby improving the signal to noise ratio of measurements made with functional magnetic resonance imaging. A spatio-temporal haemodynamic model is extended to calculate the BOLD response and determine the main properties of waves induced by moving stimuli. From this, the optimal conditions for stimulating shock-like responses are determined, and ways of inducing these responses in experiments are demonstrated in a pilot study.
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia tlacy@physics.usyd.edu.au.|Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia.
authors.forename: T C
authors.identifier: 0000-0002-0755-5119
authors.initials: TC
authors.lastname: Lacy
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia.|Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia.|Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: K M
authors.identifier: 0000-0002-7435-0236
authors.initials: KM
authors.lastname: Aquino
authors.affiliation: School of Physics, University of Sydney, New South Wales, Australia.|Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia.
authors.forename: P A
authors.initials: PA
authors.lastname: Robinson
authors.affiliation: School of Psychology, University of Wollongong, Wollongong, New South Wales 2522, Australia.|Neuroscience Research Australia, Royal Hospital for Women, Randwick, New South Wales 2031, Australia.
authors.forename: M M
authors.identifier: 0000-0002-7945-0498
authors.initials: MM
authors.lastname: Schira
mesh_terms: D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008955:Models, Cardiovascular; D008959:Models, Neurological; D010775:Photic Stimulation; D014793:Visual Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging*
keywords: blood oxygen level dependent (BOLD); functional magnetic resonance imaging; haemodynamics; shocks; spatio-temporal