Expression of green fluorescent protein (GFP) after injection of lentivirus into the adult spinal cord. Recombinant lentivirus transduces neurons in spinal cord gray matter (gm) identified by NeuN labeling (red in A and B) and glia in the spinal cord white matter (wm). (C) GFP expressing astrocytes identified by GFAP labeling (red) can also be detected.