Figure 2. Spatial profile of capillary leakage at pericyte soma and nonsoma locations. a, Schematic showing leakage site occurring at a pericyte soma and 16 ROIs used for the quantification in c. ROI dimensions were 8 × 8 × 16 μm in the x-, y-, and z-planes. The ROI of greatest leakage volume was placed at the central ROI (ROI 8). b, Representative 3-D renderings of intravenous dye extravasation at a pericyte soma (red arrow). ROIs (purple, showing actual volume occupied by intravenous dye) were strung along the capillary segment to quantify the volume of dye at preocclusion and 30 min postocclusion. The site of plasma leakage is shown with a white arrow. c, Mean intravenous dye volume per ROI for five pericyte soma leakage sites (over three mice). The location of the pericyte somata, from the tdTomato channel, corresponds with the ROIs with the greatest volume of extravasated dye. The green trace is data from the specific leakage site shown in b. *p < 0.05 and **p < 0.01 denote a significant volume increase from preocclusion values for the same ROI; multiple paired t tests. ROI 3, p = 0.033; ROI 6, p = 0.012; ROI 7, p = 0.003; ROI 8, p = 0.012; ROI 9, p = 0.019; ROI 10, p = 0.035. Data are shown as the mean ± SEM. d–f, Equivalent analyses shown in panels (a–c) for five leakage sites (over three mice) occurring in the absence of a pericyte soma. In f, pericyte somata for four of five cases were present in the sampled regions, but the positions of these somata were not correlated with the peak leakage volume. *p < 0.05 and **p < 0.01 denote a significant volume increase from preocclusion values for the same ROI; multiple paired t tests. ROI 1, p = 0.031; ROI 7, p = 0.015; ROI 8, p = 0.001; ROI 9, p = 0.042. Data shown as the mean ± SEM.