Topographic Maps: Motor Axons Wait Their Turn Kristen P. D’Elia, Jeremy S. Dasen  Current Biology  Volume 28, Issue 2, Pages R86-R88 (January 2018) DOI: 10.1016/j.cub.2017.11.047 Copyright © 2017 Elsevier Ltd Terms and Conditions

Figure 1 Temporal mechanisms of topographic mapping. (A) Schematic of olfactory bulb innervation by olfactory receptor neurons (ORNs). Birthdate differences between groups of ORNs determine axonal projection timing differences. The time when axons reach the olfactory bulb determines their target area or glomerulus. Adapted from Eerdunfu et al. [12]. (B) Schematic of the innervation of the pharyngeal arches and visceral targets by neurons of the vagus nucleus. Neurons have no differences in birthdate order along the anterior–posterior axis, but more posterior neurons delay the initiation of axons. This delay staggers projections into the periphery and influences target choice. The discovery of this new mechanism of temporal control by Barsh et al. was published in a recent issue of Current Biology [1]. Current Biology 2018 28, R86-R88DOI: (10.1016/j.cub.2017.11.047) Copyright © 2017 Elsevier Ltd Terms and Conditions