Schematic diagram of experimental design. A: To induce spinal cord injury, a 35 g circular rod was placed on the exposed L3 spinal segment and the spinal cord compressed in the dorso-ventral direction for 15 minutes. B: Three days after injury, the animals were randomly assigned to experimental groups and received a spinal graft of HSSC or media only. A total of 12 injections were performed targeting the injury epicenter and adjacent areas (see Spinal Injection Map). C: After spinal injections, the animals survived for two months while being continuously immunosuppressed and periodically tested for recovery of motor/sensory functions, changes in motor evoked potentials (MEPs) and gastrocnemius muscle spasticity response evoked by computer-controlled ankle rotation. D: At two months after treatment, animals were perfusion fixed with 4% PFA and spinal cord MRI-imaged in situ before histological processing. E: After MRI imaging, spinal cords were dissected from the spinal column and spinal blocks prepared for plastic embedding (injury epicenter region) or cryostat sectioning and used for immunofluorescence staining (the regions just above and below the injury epicenter). HSSC, human fetal spinal cord-derived neural stem cells; MRI, magnetic resonance imaging; PFA, paraformaldehyde.