title: Changes in effective diffusivity for oxygen during neural activation and deactivation estimated from capillary diameter measured by two-photon laser microscope.
abstract: The relation between cerebral blood flow (CBF) and cerebral oxygen extraction fraction (OEF) can be expressed using the effective diffusivity for oxygen in the capillary bed (D) as OEF = 1 - exp(-D/CBF). The D value is proportional to the microvessel blood volume. In this study, changes in D during neural activation and deactivation were estimated from changes in capillary and arteriole diameter measured by two-photon microscopy in awake mice. Capillary and arteriole vessel diameter in the somatosensory cortex and cerebellum were measured under neural activation (sensory stimulation) and neural deactivation [crossed cerebellar diaschisis (CCD)], respectively. Percentage changes in D during sensory stimulation and CCD were 10.3 ± 7.3 and -17.5 ± 5.3 % for capillary diameter of <6 μm, respectively. These values were closest to the percentage changes in D calculated from previously reported human positron emission tomography data. This may indicate that thinner capillaries might play the greatest role in oxygen transport from blood to brain tissue.
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.|Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan. takuwa@nirs.go.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takuwa
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Tajima
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.|Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Urushihata
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Taniguchi
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ikoma
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Seki
authors.affiliation: Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ibaraki
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.|Center for Frontier Science and Engineering, University of Electro-Communications, Chofu, Tokyo, Japan.
authors.forename: Kazuto
authors.initials: K
authors.lastname: Masamoto
authors.affiliation: Biophysics Program, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Kanno
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D002196:Capillaries / Q000378:metabolism / Q000502:physiology*; D002531:Cerebellum / Q000378:metabolism / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000379:methods; D010100:Oxygen / Q000378:metabolism*; D013003:Somatosensory Cortex / Q000378:metabolism / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology
chemical_list: D010100:Oxygen
keywords: Brain imaging; Capillary; Cerebral blood flow; PET; Two-photon laser microscope