title: Contribution of low- and high-flux capillaries to slow hemodynamic fluctuations in the cerebral cortex of mice.
abstract: We employed optical coherence tomography to measure cerebral cortical capillary red blood cell (RBC) flux in mice. The results suggest that baseline-flux weakly depends on cortical depth. Furthermore, under hypercapnia, low baseline-flux capillaries exhibit greater flux increases while the higher ones saturate, resulting in RBC-flux homogenization. Power-spectrum analysis indicates that higher flux capillaries saw greater flux variability in the low-frequency range (0.01-0.1 Hz) both at baseline and during hypercapnia. These results suggest that lower baseline-flux capillaries have more reserve to deliver oxygen with increased blood flow; but higher ones more strongly impact the low-frequency fluctuations associated with BOLD fMRI measurements of resting state functional connectivity.
authors.affiliation: Department of Electrical Engineering, École Polytechnique de Montréal, Canada Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, USA baoqiang.li@mgh.harvard.edu.
authors.forename: Baoqiang
authors.initials: B
authors.lastname: Li
authors.affiliation: Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, USA.
authors.forename: Jonghwan
authors.initials: J
authors.lastname: Lee
authors.affiliation: Optics Division, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Boas
authors.affiliation: Department of Electrical Engineering, École Polytechnique de Montréal, Canada.
authors.forename: Frederic
authors.initials: F
authors.lastname: Lesage
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D002196:Capillaries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002533:Cerebral Angiography; D002540:Cerebral Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004912:Erythrocytes / Q000166:cytology / Q000502:physiology; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008815:Mice, Inbred Strains; D008833:Microcirculation / Q000502:physiology; D041623:Tomography, Optical Coherence
keywords: Capillaries; OCT; flux; low frequency; oscillation