Fig. 2. Axonal projections into the macroglomerular complex (MGC) of olfactory receptor neurons (ORNs) after activity-dependent neurobiotin staining. ORN (yellow) in a red -synapsin-labeled background. Left panel: confocal micrographs displaying part of the neuron. Note that to visualize large parts of the neuron several confocal sections were overlayed, which blurs glomerular delineations. Right panel: three-dimensional reconstruction of the two large MGC glomeruli (lateral, pink; medial, blue) and axonal projection of the ORN (green). For clarity, the glomerulus receiving axonal input is also shown excised from the MGC. (A) Anterograde staining of Z-male Z11-14:OAc-specific ORN. ORN axonal branches arborize in the medial glomerulus. (B) Anterograde staining of Z-male E11-14:OAc-specific ORN. Axonal arbors were found exclusively in the lateral MGC glomerulus. (C) Anterograde staining of E-male E11-14:OAc-specific ORN. Synapses are exclusively limited to the medial MGC glomerulus. (D) Anterograde staining of E-male Z11-14:OAc-specific ORN. Here the axon exclusively arborizes in the lateral MGC compartment. Scale bars, 50 µm.