Fig. 1

Mouse pyramidotomy model in neonates and adults. a-d, Representative images of immunohistochemistry for PKCγ (a corticospinal tract (CST) marker) using the cervical cord of mice 4 weeks after injury. The dorsal column of sham (a, c) or pyramidotomy (b, d) groups, which were injured at P7 (a, b) or 8 weeks of age (c, d), are shown. White broken lines indicate the denervated side of the CST. e-h, To visualize axons of the intact side of corticospinal neurons (CSNs), biotinylated or rhodamine conjugated dextran amine was injected into the intact side of CSNs and fluorescence-conjugated streptavidin or anti-rhodamine antibody following fluorescence-conjugated secondary antibody was applied to the section of the cervical cord. The axonal tracer was injected 2 weeks after injury and the mice were sacrificed 4 weeks after injury. The cervical cord of sham (e, g) or pyramidotomy (f, h) groups, which were injured at P7 (e, f) or 8 weeks of age (g, h), are shown. Signals are indicated in white. The dorsal side is at the top, ventral is bottom, left is to the left, and right is to the right. Scale bars: 100 (a-d) or 500 μm (e-h). i-k, Quantification of the number of sprouting axon. The number of axons crossing midline (i; Mid), proximal (j; Z1, one third from midline to the limb of gray matter) or distal part of denervated side of the gray matter (k; Z2, two thirds from midline to the limb of gray matter) normalized by the number of labeled axon at CST were calculated. 11 slices from 3 P7 sham mice (3–4 slices/mouse), 10 slices from 3 P7 pyramidotomised mice (3–4 slices/mouse), 20 slices from 4 8 W sham mice (3–6 slices/mouse), or 19 slices from 4 8 W pyramidotomised mice (3–6 slices/mouse) were used for quantification. Mean ± S.E.M.; *P < 0.05, Tukey’s honestly significant difference (HSD) test