title: Interdependence of regional and global cerebral blood flow during visual stimulation: an O-15-butanol positron emission tomography study.
abstract: The authors investigated the influence of variations in global cerebral blood flow (gCBF) on regional flow changes during visual stimulation. Global flow was varied using different end-expiratory CO2 values (PETCO2) between 20 and 70 mm Hg. Visual stimulation was performed with a red LED-array flashing at 8 Hz. Blood flow was measured with 0-15-butanol, continuous arterial blood sampling, and positron emission tomography (PET). Global flow changes surpassed the published values of O-15-H2O studies, better fitting the results of the inert gas technique (gCBF at 20, 40, and 70 mm Hg PETCO2 +/- SD was 31 +/- 4, 48 +/- 13, and 160 +/- 50 mL 100 g(-1) min(-1), respectively). The relation between PETCO2 and CBF in the current study was best described by an exponential rather than a linear function. At low PETCO2, the activation-induced flow changes are moderately damped, whereas at high PETCO2, they are nearly lost (deltaCBF (+/-SD): 52% +/- 25%, 68% +/- 22%, 16% +/- 25% at PETCO2 = 20, 40, 70 mm Hg, respectively).
authors.affiliation: Institut für Medizin, Forschungszentrum Jülich, Germany.
authors.forename: L J
authors.initials: LJ
authors.lastname: Kemna
authors.forename: S
authors.initials: S
authors.lastname: Posse
authors.forename: L
authors.initials: L
authors.lastname: Tellmann
authors.forename: T
authors.initials: T
authors.lastname: Schmitz
authors.forename: H
authors.initials: H
authors.lastname: Herzog
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000098:blood supply*; D000440:Butanols; D002245:Carbon Dioxide / Q000008:administration & dosage / Q000032:analysis / Q000097:blood; D006339:Heart Rate; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000097:blood; D010104:Oxygen Radioisotopes; D010775:Photic Stimulation; D011659:Pulmonary Gas Exchange; D014055:Tomography, Emission-Computed
chemical_list: D000440:Butanols; D010104:Oxygen Radioisotopes; D002245:Carbon Dioxide; D010100:Oxygen