Representative images of leukocyte-endothelium interaction (LEI) at a depth of 100 to 150 μm. The vessel lumen is stained with fluorescein isothiocyanate-labeled (FITC) dextran (green), and leukocytes are labeled with rhodamine 6 G (red). Eight hours after controlled cortical impact (CCI) leukocytes and leukocyte-platelet aggregates interact with the endothelium at a depth of 100 to 150 μm (lower panel). In contrast, there were few leukocyte-endothelium interactions under normal physiological conditions (that is, 8 h after a sham operation; upper panel). All three axes of the calibration bar are 50 μm.