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.