Harnessing endogenous stem cells to treat neurodegenerative disorders of the basal ganglia.

New neurons are continuously generated in selective regions of the normal adult mammalian brain. Recent evidence suggests that neural stem or progenitor cells located in the subventricular zone lining of the lateral ventricles can be induced to proliferate and migrate to the adjacent striatum following brain insults or growth factor treatment. This ability to incorporate new cells into the striatum gives the potential of repairing and restoring basal ganglia functions in Parkinson's and Huntington's diseases. The future challenges lay in directing these new cells to adopt the appropriate neuronal phenotypes and to re-establish proper connections and functional circuitry.