White matter sparing at the SCI epicenter.Top, Bottom Left, Photomicrographs of representative sections through the lesion epicenter from the three SCI groups and from an uninjured control stained with eriochrome cyanine to label myelin. The dorsal, lateral, and ventral funicular white matter of the normal spinal cord is heavily stained, whereas little myelin staining is seen in the central gray matter. The cross-sectional profiles of the injured spinal cords are reduced in diameter. The center of the injured cords contains cavities and an abnormal loose network of cells, but no myelin staining is apparent. A peripheral rim of residual white matter is seen. Myelin staining is present but reduced compared with normal white matter, consistent with the chronic hypomyelination of residual axons. Bottom Right, The average areas of myelinated white matter from the ventral and lateral funicular zones at the lesion epicenter in the SCI groups. One asteriskindicates a significant difference from the 12.5 mm SCI group, based onp < 0.05 in Tukey's post hoc test after ANOVA. Scale bar, 250 μm.