Fig. 6

Systematic morphometric analysis of grouped ORNs. a–e Volumes of the soma, inner and outer dendrites of the paired ORNs in five sensillum types. (Left) Sample 3D reconstruction based on SBEM images. Arrows indicate the cilium base, a constricted region separating the inner and outer dendrites. Due to technical limitations, the outer dendrites of most basiconic sensilla could not be completely reconstructed (see Methods for details). Scale bars: 2 µm. Lines connect measurements from paired ORNs, mean ± s.e.m. n = 4–5 for all except for at4, n = 8. *P < 0.05, **P < 0.01, ***P < 0.001, paired t test. The P values are a 0.00004 and 0.001; b 0.033 and 0.003; c 0.0004, 0.035, and 0.008; d 0.004, 0.041, and 0.017; e 0.125 and 0.001. Error bars and statistics are unavailable for the ab5 outer dendrites as only two data points were obtained. f, g Novel morphological features. f An enlargement of the inner dendrite (arrow head) was observed in the “A” ORNs in all three characterized basiconic sensilla. g A bend or loop (arrow head) was observed in the unbranched outer dendrite of the ab4 ORNs. Scale bar: 500 nm. Source data are provided as a Source Data file. ORN olfactory receptor neuron, SBEM serial block-face scanning electron microscopy