The average number of traced RtST collaterals that entered the grey matter (normalized to traced RtST axon count and the length of the section analyzed) was similar between dSTAG (3.0 x [10.sup.-6] [+ or -] 0.7 x [10.sup.-6] collaterals/traced axon/[micro]m) and cSTAG (1.4 x [10.sup.-6] [+ or -] 0.4 x [10.sup.-6] collaterals/traced axon/[micro]m) animals (p = 0.12; Figures 5(a) and 5(b)).
Multiple comparisons showed that the dSTAG group had significantly more collateral intersections 425 [micro]m from the grey/white matter interface (p < 0.05).
Interestingly, more synaptic connections with PrINs were found when the second SCI was delayed by 2 weeks (dSTAG) compared to animals that received both SCIs at the same time (cSTAG), which could explain the superior recovery of these animals.
However, dSTAG collaterals exhibited enhanced growth compared to cSTAG collaterals.
Superior recovery of dSTAG animals could also be because rats with spared white matter in one hemicord recover locomotor movements quickly and are very active in their cages (also because the leg opposite the SCI is largely functional) .
Contralateral hindlimb function of the dSTAG and cSTAG groups was similar.
Caption: Figure 2: dSTAG animals displayed superior locomotor ability compared to cSTAG animals.
Schematics of spinal cord segments encompassing the lesions from representative dSTAG and cSTAG animals (c).
No significant differences in the number of soma in the grey matter were found between dSTAG and cSTAG groups (c).