Neurotransplantation in neurodegenerative disease: a survey of relevant issues in developmental neurobiology.

Neural development and transplantation therapies in neurodegenerative disease share a particular feature. In both cases, undifferentiated neural precursor cells are required to differentiate into a range of neural cell types in a tissue-specific fashion. This similarity opens the possibility that the mechanisms that drive neural development play a similar role in CNS repair. In this chapter, two aspects of neural development are considered in terms of their relevance to CNS repair: the diversity of neural precursor cells and positional specification. We present evidence to suggest that neural stem cells have a degree of diversity that is beyond what might have been expected a priori. We also show that neural stem cells express genes that might encode a positional specification for these cells, and consider a number of hypotheses about the role of positional specification in CNS repair.