Neuronal regeneration: Lessons from the olfactory system

Neuronal regeneration takes place in the primary relay of the olfactory sys tem, the olfactory epithelium (OE); however; ifs synaptic target in the cen tral nervous system, the olfactory bulb (OB), undergoes continual neurogene sis but not true regeneration. In this review, cell interactions and growth factors regulating neurogenesis in both OE and OB are discussed. In additi on, regulation of regeneration in the OE and regulation of neurogenesis in the OB are compared, with the goal of identifying characteristics that may account for the different abilities of these two tissues to regenerate.