FIG. 4.

Cervical level contusive injury results in anatomical and functional deficits. Horizontal sections stained with antibody against pseudorabies virus (PRV, brown) and counter stained with cresyl violet (CV, blue) through the injured (non-transplanted) cervical spinal cord 1 month after injury ranging from dorsal to ventral parts of the spinal cord (A). PRV labeling was used to retrogradely label the phrenic motor circuit, demonstrating that the injury is located primarily on the rostral-most part of the phrenic motor nucleus (A, inset). (B) An overlay of schematic diagrams of spinal cord cross sections of five injured animals through the lesion epicenter demonstrates reproducible anatomical damage 1 month after contusion injury. (C) Quantitative analysis of the change in diaphragm output as a response to hypoxic (non-shaded bar graphs) and hypercapnic (shaded bar graphs) respiratory challenges reveals the distribution of average diaphragm activity 1 (n = 3), 5 (n = 3), and 6 (n = 6) weeks after injury. Each point represents the percent change of diaphragm output during a respiratory challenge for each individual animal that was able to survive 5 min of the challenge. Dotted line represents response to challenge seen in naïve (non-injured), age-matched animals. Scale bars are as indicated. DH, dorsal horn; IG, intermediate gray; VH, ventral horn; cc; central canal; vf; ventral fissure.