that a quiescent NSCs population in DRG may continue neurogenesis through adulthood with declines in neuron number occurring in old age. Recently, we and others have demonstrated that a protracted maturation process persists in trigeminal and dorsal root ganglia and a population of undifferentiated neural crest cells remains into adulthood (23,25). Our current results further demonstrated that a population of cells with stem cell potential are not only preserved, but also after ex vivo can remain dormant for years after being awakened for differentiation of native phenotypes.
