RT Journal Article SR Electronic T1 Systematic morphological and morphometric analysis of identified olfactory receptor neurons in Drosophila melanogaster JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.04.28.441861 DO 10.1101/2021.04.28.441861 A1 Gonzales, Cesar Nava A1 McKaughan, Quintyn A1 Bushong, Eric A A1 Cauwenberghs, Kalyani A1 Ng, Renny A1 Madany, Matthew A1 Ellisman, Mark H A1 Su, Chih-Ying YR 2021 UL http://biorxiv.org/content/early/2021/04/29/2021.04.28.441861.abstract AB The biophysical properties of sensory neurons are influenced by their morphometric and morphological features, whose precise measurements require high-quality volume electron microscopy (EM). However, systematic surveys of these nanoscale characteristics for identified neurons are scarce. Here, we characterize the morphology of Drosophila olfactory receptor neurons (ORNs) across the majority of genetically identified sensory hairs. By analyzing serial block-face electron microscopy (SBEM) images of cryofixed antennal tissues, we compile an extensive morphometric dataset based on 122 reconstructed 3D models of 33 identified ORN types. In addition, we observe multiple novel features—including extracellular vacuoles within sensillum lumen, intricate dendritic branching, mitochondria enrichment in select ORNs, novel sensillum types, and empty sensilla containing no neurons—which raise new questions pertinent to cell biology and sensory neurobiology. Our systematic survey is critical for future investigations into how the size and shape of sensory neurons influence their responses, sensitivity and circuit function.Competing Interest StatementThe authors have declared no competing interest.