title: Large arteriolar component of oxygen delivery implies a safe margin of oxygen supply to cerebral tissue.
abstract: What is the organization of cerebral microvascular oxygenation and morphology that allows adequate tissue oxygenation at different activity levels? We address this question in the mouse cerebral cortex using microscopic imaging of intravascular O2 partial pressure and blood flow combined with numerical modelling. Here we show that parenchymal arterioles are responsible for 50% of the extracted O2 at baseline activity, and the majority of the remaining O2 exchange takes place within the first few capillary branches. Most capillaries release little O2 at baseline acting as an O2 reserve that is recruited during increased neuronal activity or decreased blood flow. Our results challenge the common perception that capillaries are the major site of O2 delivery to cerebral tissue. The understanding of oxygenation distribution along arterio-capillary paths may have profound implications for the interpretation of blood-oxygen-level dependent (BOLD) contrast in functional magnetic resonance imaging and for evaluating microvascular O2 delivery capacity to support cerebral tissue in disease.
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Sava
authors.initials: S
authors.lastname: Sakadžić
authors.affiliation: Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Emiri T
authors.initials: ET
authors.lastname: Mandeville
authors.affiliation: 1] Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA [2] Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada H3C3A7.
authors.forename: Louis
authors.initials: L
authors.lastname: Gagnon
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Musacchia
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Yaseen
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Meryem A
authors.initials: MA
authors.lastname: Yucel
authors.affiliation: Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada H3C3A7.
authors.forename: Joel
authors.initials: J
authors.lastname: Lefebvre
authors.affiliation: Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada H3C3A7.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lesage
authors.affiliation: Departments of Radiology and Neurosciences, University of California San Diego, La Jolla, San Diego, California 92093, USA.
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
authors.affiliation: Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Katharina
authors.initials: K
authors.lastname: Eikermann-Haerter
authors.affiliation: 1] Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA [2] Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Cenk
authors.initials: C
authors.lastname: Ayata
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Vivek J
authors.initials: VJ
authors.lastname: Srinivasan
authors.affiliation: Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Eng H
authors.initials: EH
authors.lastname: Lo
authors.affiliation: 1] Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA [2] Departments of Radiology and Neurosciences, University of California San Diego, La Jolla, San Diego, California 92093, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Devor
authors.affiliation: Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Boas
mesh_terms: D000818:Animals; D001160:Arterioles / Q000502:physiology; D001921:Brain / Q000098:blood supply* / Q000502:physiology; D002196:Capillaries / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008853:Microscopy; D008962:Models, Theoretical; D064847:Multimodal Imaging; D009474:Neurons / Q000502:physiology; D010100:Oxygen / Q000737:chemistry*; D010101:Oxygen Consumption / Q000502:physiology*
chemical_list: D010100:Oxygen