Figure 10

Anterograde labelling of CST axons after spinal cord injury and LPS application. Horizontal sections through spinal cord injury sites (Figs 10a, b), and a transverse section through the medulla (Fig. 10c) 21 days after lesion of the CST at C4 with either simultaneous injection of BDA into contralateral motor cortex (Control) or injection of BDA into and application of LPS onto motor cortex (LPS). In both the LPS-treated (Fig. 10b) and control tissue (Fig. 10a), end bulbs are seen at the tips of large numbers of axons. There is little sign of axon branching into the contralateral CST, and the labelled axons extending into the lesion site are located in a strand of spared tissue that extends no more than 50 μm. No axons appear to circumnavigate or regenerate beyond the lesion site. The white boxes correspond to the counting frame windows. Fig. 10c shows BDA-labelled CST axons in the pyramid of the medulla (midline at arrow). All images are confocal; * = lesion site; R = rostral; L = lateral; P = pyramid; scale bar in Fig. 10a = 100 μm and also applies to Fig. 10b; bar in Fig. 10c = 200 μm.