Article Figures & Data
Figures
- Figure 1.
Baseline pO2 relative to diving arterioles and surfacing venules. A, An image of the surface vasculature calculated as a maximum intensity projection of an image stack 0–300 μm in depth obtained using a 4× objective. Individual images were acquired every 10 μm. The fluorescent contrast is due to intravascular FITC. The image on the right shows a zoomed-in view of the region within the red square on the left at the depth plane of pO2 measurements, 200 μm below the surface. A, Diving arteriole; V, surfacing venule. B, A grid of measured pO2 values superimposed on the vascular reference image. C, pO2 as a function of the radial distance from the center of a blood vessel: diving arterioles (left) or surfacing venules (right). The pO2 values were obtained from grid measurements, as with the example in A and B. Data from multiple vessels from multiple animals are overlaid on each plot.
- Figure 2.
Distribution of the measured pO2 values as a function of cortical depth. Categories and numbers of samples are indicated above the histograms.
- Figure 3.
Tissue pO2 changes in response to transient stimulation. A, B, An example set of measurements from a plane 300 μm below the cortical surface. A, Points used to measure stimulus-evoked responses, color-coded according to the prestimulus (baseline) pO2, are superimposed on the vascular reference image. A corresponding FITC image of the surface vasculature is shown on the left. B, Time courses of pO2 change extracted from each point shown in A. The thick black curve shows the average. The red arrow in this and other figures indicates stimulus onset. C, Averaged time courses, grouped according to the baseline pO2. The groups are indicated on the right. The inset shows mean peak pO2 increase from the baseline (ΔpO2) for each baseline category. The error bars represent SE across subjects. D, The same data as in C. The averaged time courses are grouped according to the baseline, above and below 14 mmHg. E, The same time courses as in D, baseline-subtracted and normalized to the peak amplitude.
- Figure 4.
Tissue pO2 changes in response to sustained stimulation. A, Averaged pO2 time courses in response to the 20 s stimulus. The data were grouped according to the baseline pO2. The groups are indicated on the right. The red line shows the average. The inset shows mean pO2 increase from the baseline (ΔpO2) during the plateau response for each baseline category. The error bars represent SE across subjects. B, A zoomed-in view of the first 10 s during the sustained stimulus (dashed line). The response to 2 s stimulus, group-averaged using the same baseline bins, is overlaid in solid black.
