title: Simultaneous monitoring of dynamic changes in cerebral blood flow and oxygenation during sustained activation of the human visual cortex.
abstract: Functional neuroimaging was used to investigate the effect of cerebral blood flow (CBF) adjustments on the blood oxygenation level dependent (BOLD) signal during visual stimulation. Temporal responses from both oxygenation- and perfusion-sensitized MRI revealed almost identical features during onset and ongoing activation, i.e. an activation-induced signal rise, and a gradual signal decrease during prolonged activation (overshoot). However, the post-stimulus responses exhibited a pronounced BOLD signal drop below prestimulus baseline (undershoot), but a rather rapid normalisation of the related CBF signal. Thus, an activation-induced initial BOLD signal rise and a gradual signal decrease reflect a coarse upregulation of CBF, which is followed by fine-tuning adjustments of flow. Regulations of other involved physiological parameters, including blood volume and oxidative metabolism give rise to a negative post-stimulus BOLD signal response.
authors.affiliation: Lucas MRS Center, Department of Radiology, Stanford University, Palo Alto, CA 94305, USA.
authors.forename: G
authors.initials: G
authors.lastname: Krüger
authors.forename: A
authors.initials: A
authors.lastname: Kastrup
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: G H
authors.initials: GH
authors.lastname: Glover
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000097:blood*; D010775:Photic Stimulation; D013997:Time Factors; D015854:Up-Regulation; D014793:Visual Cortex / Q000502:physiology*
chemical_list: D010100:Oxygen