From the past six months of work, we report considerable progress toward our aims of investigating the safety and efficacy of human inhibitory nerve precursor (MGE) cell transplantation for the treatment of spinal cord injury-induced bladder spasticity and neuropathic pain. Our first aim details the injection of human MGE cells into the uninjured rodent spinal cord and investigation of cell fate and potential adverse side effects from their transplantation. During the reporting period, we completed histological analyses for the two-month time point post-injection, and we found that the human MGE cells, derived from human embryonic stem cells (hESCs), appropriately matured into forebrain-type inhibitory interneurons in the rodent spinal cord. Also, we initiated histological examination of animals six months post-injection and detected robust human cell survival, dispersal into the spinal cord grey matter, and neuronal maturation, but no evidence of tumor formation. In addition, we completed behavioral analyses of animals injected with hESC-derived MGE cells at two and six months post-injection. Thus far, we have not observed any adverse side effects when human MGE cells are transplanted into the uninjured animal as determined by measures of body weight, locomotion, bladder function, and pain sensitivity.