CXCR4-GFP cells appear in the periphery and in the dorsal funiculus in 2 weeks. At 24 hours post injury, CXCR4-GFP cells appear throughout the gray and white matter, but this expression is gone by 4 days post injury(a-f). The ependymal layer, which was full of CXCR4-GFP prior to injury, has fewer CXCR4-GFP cells post injury (a-b, d-e, g-h, j-k). A sprinkling of CXCR4-GFP cells are seen toward the meninges at 1 week(g-i), but the majority of the 2 apparently migrating populations arrive by 2 weeks(j, l-o). Caudal to the injury, no cells are again seen in the dorsal funiculus(k).(green:CXCR4-EGFP, blue:Hoechst). Scale bars: a, d, g, j-k: 200 μm, b-c, e-f, h-I, k-l: 50 μm, m-o: 25 μm.