Figure 3. Monitor display presented by NIH Image software of triphenyltetrazolium-stained brain sections. The software presents a look-up Table of256 colors in the image. As described in text, the look-up Table hasbeen re-sorted to aid selection and subsequent counting of all pale (non-staining) pixels. In each panel, coronal brain sections are shown from animals having (from top to bottom) the minimum, median, and maximum percentages of nonstaining pixels in their respective groups. (A) Surgical shams. (B) 200 [micro sign]l/kg intracarotid air. (C) 300 [micro sign]l intracarotid saline. (D) 50 [micro sign]l/kg intracarotid air.