Chronic neuronal activation in the dorsal horn resulted from cervical contusion SCI.

<p>ΔfosB staining was used to measure the extent of persistent neuronal activation in the spinal cord. Following injury, ΔfosB-positive nuclei (arrowheads) were evident in laminae I–II (A–C). At all regions, laminectomy control animals (A) showed little-to-no ΔfosB expression (D). Two weeks after C6 injury (B), a significant increase in numbers of ΔfosB expressing cells in the superficial laminae of the ipsilateral dorsal horn was observed at the injury epicenter and caudal to the injury (D). ΔfosB levels were further increased at all regions in animals sacrificed six weeks post-injury (C, D). * = p<0.05; ** = p<0.01; *** = p 0.001; **** = p<0.0001.