A major goal of stem cell research is to generate various functional human cell types to promote repair or replacement in injury or disease. Our lab studies the repair of central nervous system after injury such as a spinal cord injury. We have been utilizing a fluorescent reporter line we developed with CIRM funding to enrich and characterize human corticospinal motor neurons, a neuronal population that is damaged or lost in spinal cord injury and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease). These neurons control skilled voluntary movement in humans, the loss or damage of which leads to paralysis and disability. We have made significant progress in this funding period. We validated that our fluorescent reporter works as intended. We found that reporter gene expression represents cells of different developmental stages at different times of differentiation. We have done the first batches of transplantation studies to show that it is possible to use the reporter gene to track the cells and cellular processes in the host central nervous system. In addition, we have developed a separate reporter gene to universally mark all embryonic stem-derived cells, a tool that may be useful to other stem cell researchers. We are now ready to move to the next phase of the project: to characterize corticospinal motor neurons in more detail in vitro and in vivo. Knowledge gained from this study will pave the way to make better disease-models-in-a-dish for neurological conditions such as ALS and to develop therapies for ALS, spinal cord injury, traumatic brain injury, stroke and other neurological conditions when corticospinal motor neurons are damaged of lost.