New Neurons in the Postnatal Olfactory System: Functions in the Healthy and Regenerating Brain.

The rodent olfactory system is unique in harboring two distinct postnatal neurogenic niches, the olfactory epithelium and the subventricular zone. This results in the ongoing generation of both olfactory sensory neurons (OSNs), which provide odor input to the brain, and multiple molecularly distinct populations of GABAergic interneurons that modulate both input to and output from the olfactory bulb, continuing throughout life for some neuronal types. Here, we review the roles played by these postnatally generated neurons in olfactory processing, plasticity and regeneration. We identify specific roles for individual types of postnatally generated neurons, as well as identifying overarching principles that span multiple neuronal types.