scholarly journals Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

2012 ◽  
Vol 32 (7) ◽  
pp. 1277-1309 ◽  
Author(s):  
Andy Y Shih ◽  
Jonathan D Driscoll ◽  
Patrick J Drew ◽  
Nozomi Nishimura ◽  
Chris B Schaffer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Scanning ◽  
Vascular System ◽  
Neurovascular Coupling ◽  
Laser Scanning Microscopy ◽  
Small Scale ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Rats And Mice ◽  
The Brain

The cerebral vascular system services the constant demand for energy during neuronal activity in the brain. Attempts to delineate the logic of neurovascular coupling have been greatly aided by the advent of two-photon laser scanning microscopy to image both blood flow and the activity of individual cells below the surface of the brain. Here we provide a technical guide to imaging cerebral blood flow in rodents. We describe in detail the surgical procedures required to generate cranial windows for optical access to the cortex of both rats and mice and the use of two-photon microscopy to accurately measure blood flow in individual cortical vessels concurrent with local cellular activity. We further provide examples on how these techniques can be applied to the study of local blood flow regulation and vascular pathologies such as small-scale stroke.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

scholarly journals Quantitative hemodynamic analysis of cerebral blood flow and neurovascular coupling using optical coherence tomography angiography

2018 ◽  
Vol 39 (10) ◽  
pp. 1983-1994 ◽  
Author(s):  
Paul Shin ◽  
WooJhon Choi ◽  
JongYoon Joo ◽  
Wang-Yuhl Oh
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Laser Scanning ◽  
Neurovascular Coupling ◽  
Laser Scanning Microscopy ◽  
Oct Angiography ◽  
Wide Field ◽  
Optical Coherence ◽  
Arterial Blood ◽  
Doppler Oct

Functional hyperemia in the rat cortex was investigated using high-speed optical coherence tomography (OCT) angiography and Doppler OCT. OCT angiography (OCTA) was performed to image the hemodynamic stimulus-response over a wide field of view. Temporal changes in vessel diameters in different vessel compartments, which were determined as the diameters of erythrocyte flows in OCT angiograms, were measured in order to monitor localized hemodynamic changes. Our results showed that the dilation of arterioles at the site of activation was accompanied by the dilation of upstream arteries. Relatively negligible dilation was observed in veins. An increase in the OCTA signal was observed during stimulus in multiple capillaries, which may imply that capillary blood flow increases as a result of the expanded arterial blood volume. These results agree with previous observations using two-photon laser scanning microscopy (TPLSM). Doppler OCT was performed to quantitatively measure stimulus-induced blood flow response in pial arteries. The measurement showed small but clear hemodynamic response in upstream arteries with diameters exceeding 100 [Formula: see text]m. Our results demonstrate the potential of OCTA and Doppler OCT for the investigation of neurovascular coupling in small animal models.

scholarly journals Changes in Cortical Microvasculature during Misery Perfusion Measured by Two-Photon Laser Scanning Microscopy

2014 ◽  
Vol 34 (8) ◽  
pp. 1363-1372 ◽  
Author(s):  
Yosuke Tajima ◽  
Hiroyuki Takuwa ◽  
Daisuke Kokuryo ◽  
Hiroshi Kawaguchi ◽  
Chie Seki ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Vascular Response ◽  
Doppler Flowmetry ◽  
Cerebrovascular Reserve ◽  
Two Photon ◽  
Misery Perfusion

This study aimed to examine the cortical microvessel diameter response to hypercapnia in misery perfusion using two-photon laser scanning microscopy (TPLSM). We evaluated whether the vascular response to hypercapnia could represent the cerebrovascular reserve. Cerebral blood flow (CBF) during normocapnia and hypercapnia was measured by laser-Doppler flowmetry through cranial windows in awake C57/BL6 mice before and at 1,7, 14, and 28 days after unilateral common carotid artery occlusion (UCCAO). Diameters of the cortical microvessels during normocapnia and hypercapnia were also measured by TPLSM. Cerebral blood flow and the vascular response to hypercapnia were decreased after UCCAO. Before UCCAO, vasodilation during hypercapnia was found primarily in arterioles (22.9% ± 3.5%). At 14 days after UCCAO, arterioles, capillaries, and venules were autoregulatorily dilated by 79.5% ± 19.7%, 57.2% ±32.3%, and 32.0% ± 10.8%, respectively. At the same time, the diameter response to hypercapnia in arterioles was significantly decreased to 1.9% ± 1.5%. A significant negative correlation was observed between autoregulatory vasodilation and the diameter response to hypercapnia in arterioles. Our findings indicate that arterioles play main roles in both autoregulatory vasodilation and hypercapnic vasodilation, and that the vascular response to hypercapnia can be used to estimate the cerebrovascular reserve.

scholarly journals Live Intravital Intestine with Blood Flow Visualization in Neonatal Mice Using Two-photon Laser Scanning Microscopy

BIO-PROTOCOL ◽  
2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Yuhki Koike ◽  
Bo Li ◽  
Yong Chen ◽  
Niloofar Ganji ◽  
Mashriq Alganabi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Visualization ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Two Photon ◽  
Neonatal Mice

scholarly journals Rheological effects of drag-reducing polymers improve cerebral blood flow and oxygenation after traumatic brain injury in rats

2016 ◽  
Vol 37 (3) ◽  
pp. 762-775 ◽  
Author(s):  
Denis E Bragin ◽  
Marina V Kameneva ◽  
Olga A Bragina ◽  
Susan Thomson ◽  
Gloria L Statom ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Blood Flow ◽  
Brain Injury ◽  
Laser Scanning ◽  
Microvascular Perfusion ◽  
Laser Scanning Microscopy ◽  
Cerebral Microcirculation ◽  
Two Photon ◽  
Wall Cell

Cerebral ischemia has been clearly demonstrated after traumatic brain injury (TBI); however, neuroprotective therapies have not focused on improvement of the cerebral microcirculation. Blood soluble drag-reducing polymers (DRP), prepared from high molecular weight polyethylene oxide, target impaired microvascular perfusion by altering the rheological properties of blood and, until our recent reports, has not been applied to the brain. We hypothesized that DRP improve cerebral microcirculation and oxygenation after TBI. DRP were studied in healthy and traumatized rat brains and compared to saline controls. Using in-vivo two-photon laser scanning microscopy over the parietal cortex, we showed that after TBI, nanomolar concentrations of intravascular DRP significantly enhanced microvascular perfusion and tissue oxygenation in peri-contusional areas, preserved blood–brain barrier integrity and protected neurons. The mechanisms of DRP effects were attributable to reduction of the near-vessel wall cell-free layer which increased near-wall blood flow velocity, microcirculatory volume flow, and number of erythrocytes entering capillaries, thereby reducing capillary stasis and tissue hypoxia as reflected by a reduction in NADH. Our results indicate that early reduction in CBF after TBI is mainly due to ischemia; however, metabolic depression of contused tissue could be also involved.

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