Figure 6.

Simultaneous pO₂ and blood velocity measurements. (a) A CCD image of the cortical surface as seen through the chronic glass-sealed cranial window. The ROI selected for 2PM (for pO₂ measurements) is marked with a yellow square. Vertical dashed line marks the position of the Doppler OCT B-scan, used to measure the axial component of the blood velocity. The pial vessels are pseudo-colored (arterioles—red; venules—blue) on the maximum intensity projection of the 2PM angiogram, encompassing ∼40 µm depth. The white dashed circle marks the location of the surfacing venule from which simultaneous absolute pO₂ and velocity measurements are reported in (b). (c) Comparison between the percent change in axial component of the venular blood flow velocity and venular pO₂ during functional activation (n = 2). Error bars in (c) show the velocity projection standard deviation across animals. pO₂: partial pressure of O₂.