Stem cell biology is one of the most closely followed developments in biomedicine today, since stem cells may provide the foundation for rational regenerative therapeutics with far-reaching implications in the health sector. The use of stem cells to gener ate new nerve cells has received particularly heavy attention because of the limited capacity of the brain for regeneration. Despite promising findings during recent years however, it is still unclear to what degree stem cells can be used for supporting regeneration following trauma or disease to the brain and spinal cord. This is due partly to the relatively poor success in obtaining reliable differentiation to neurons in in vivo settings, which stands in apparent contrast to reports of substantial neur onal differentiation in vitro. The main goal of this research proposal is to use high-resolution magnetic resonance imaging to obtain comprehensive information about the fate of selected types of adult human and embryonic mouse stem cells in well-defined in vivo pathological situations. The stem cells to be tested are those with demonstrated potential to differentiate into nerve cells. The technical approach involves state-of-the-art stem cell labeling and magnetic resonance imaging techniques, and bring s together research groups from 4 different Norwegian institutions spanning basic research and clinical neurology. The research is expected to provide important new information about the behavior of stem cells that can in the future be used in clinical th erapies for human brain and spinal cord injuries and neurological disorders.