Our transplantation experiments address fundamental issues of potential and fate with respect to neural stem cells and lineage-restricted progenitors, as well as the development of therapeutic strategies for repair of spinal cord injury. We hypothesize that multipotent neural stem cells do not differentiate into neurons following transplantation because the stem cells fail to progress into lineage-restricted precursors. Our studies demonstrate that lineage-restricted precursor cells are a promising alternative to multipotential stem cells. Glial-restricted precursor (GRP) cells represent one of the most promising candidates for transplantation therapy because of their potential to remyelinate damaged or regenerating axons and produce permissive astrocytes (Wu et. al., 2002). Our studies demonstrate that grafted GRP cells not only survive and differentiate in the intact and injured spinal cord, but they also migrate long distances and may therefore provide a permissive environment at and around injury sites.