Spatiotemporal distribution of Col1α1-GFP⁺ cells after SCI. Col1α1-GFP⁺ cells enter the injury site between 3 and 5 dpi (A,B) and persist chronically (C–H). The cell density is highest at 7 dpi (C,K) and by 14 dpi (D) condense into a fibrous scar that apposes to the GFAP⁺ astrocytic scar (F) and are the predominant PDGFR-β⁺ cells in the scar (E). Serotonin (5HT) axons fail to penetrate the Col1α1-GFP⁺ region (L). M, Red channel in L. After dorsal hemisection, Col1α1⁺ cells also do not enter the injury site until after 3 dpi (I) and fill the injury epicenter by 14 dpi (J). LEL-labeled vasculature (red) encloses the fibrotic scar along the dense peripheral rim of Col1α1-GFP⁺ cells. N, a single LSFM section. O–V, Representative images of laminin (LN) and fibronectin (FN) expression relative to Col1α1⁺ cells in the scar. *p < 0.0001 (one-way ANOVA). Scale bars: A–J, L–V, 500 μm.