Figure 10

Hierarchical model of OSN axon sorting. OR-specific OSNs (each color represents an individual OR) are randomly distributed throughout one of approximately four zones along the dorsal-ventral axis in the OE, with no known organization along the anterior-posterior axis. OSNs each express some currently unknown constellation of guidance molecules (each pattern represents a set of guidance molecules). The OSN axons sort regionally in the mesenchyme according to the guidance molecules they express independent of their OR specificity. After the OSN axons cross into the inner nerve layer of the OB, OR-specific sorting occurs resulting in final convergence into a glomerulus.