A Critical Period Defined by Axon-Targeting Mechanisms in the Murine Olfactory Bulb

Abstract

Axon Routing in the Olfactory System The olfactory system of mice entails a developmental program that wires neurons expressing similar olfactory receptors into glomeruli together. Although the adult olfactory system continues to produce and incorporate new neurons, it cannot withstand severe damage (see the Perspective by Cheetham and Belluscio ). Ma et al. (p. 194 ) and Tsai and Barnea (p. 197 ) examined the difference in responses between early development and adulthood. Manipulating the expression of an odorant receptor or the activity of the olfactory neurons altered olfactory neuron axonal pathfinding. The results suggest that the guidance systems used differ between early development and adulthood: Early axons find their own way, but later-in-life axons can only follow existing pathways.