Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
Tatiana V Esipova
Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States; Department of Chemistry, University of Pennsylvania, Philadelphia, United States
Ikbal Sencan
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
Kıvılcım Kılıç
Department of Neurosciences, University of California, San Diego, La Jolla, United States
Buyin Fu
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
Michele Desjardins
Department of Radiology, University of California, San Diego, La Jolla, United States
Mohammad Moeini
Institute of Biomedical Engineering, École Polytechnique de Montréal, Montréal, Canada; Research Centre, Montreal Heart Institute, Montréal, Canada
Sreekanth Kura
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States; Department of Neurosciences, University of California, San Diego, La Jolla, United States; Department of Radiology, University of California, San Diego, La Jolla, United States
David A Boas
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, United States; Department of Biomedical Engineering, Boston University, Boston, United States
Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, United States; Department of Chemistry, University of Pennsylvania, Philadelphia, United States
Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.
