Embryonic motoneurons grafted into the adult CNS can differentiate and migrate

Embryonic mouse motoneurons were labelled by retrograde transport with a fluorescent dye (diI), partially purified on a densdity gradient and grafted into adult mouse CNS for a maximum of 10 weeks. In both the spinal cord and striatum, a small number of fluorescently labelled motoneurons were found to survive as judged by their round, bright appearance and also to differentiate as assessed by their ability to extend neurites. The motoneurons travelled long distances in the spinal cord (2 mm) and in the brain (4 mm) in both white and gray matter.