Schematic overview of experimental procedures.

<p>Schematic representations show pathways for the CST, RST and central axons of the DRG. A: The CST originates from the sensorimotor cortex, decussates at the medullary level of the brain stem and descends in the deep layer of the dorsal column. scAAV2-GFP vector was injected into sensorimotor cortex (green stars indicate GFP expression). Dorsal column lesion (red line in A) was performed to transect fibers of the CST in the cervical spinal cord. B: The RST runs from the neuronal bodies in the brainstem, crosses to the contralateral side and descends in the lateral white matter of the spinal cord. scAAV2-GFP was injected into the red nucleus (RN) to label the RST. C: Central axons of DRG originate from DRG neurons, pass through the dorsal root entry zone and ascend in the spinal cord dorsal column to reach the brain stem. Red lines in C indicate dorsal root crush and dorsal column lesions that transect the central axons of DRG in the dorsal root and spinal cord respectively. scAAV2-GFP was injected into DRG to anterogradely label central axons of the DRG.