fasciculates with develops from expresses sends synaptic output throughout has sensory dendrite in Or33a Or56a sensory epithelial cell antennal lobe glomerulus DA2 adult antennal lobe commissure sNPF neuron antennal olfactory receptor neuron precursor Nab antennal olfactory receptor neuron of basiconic sensillum adult antennal lobe receptor neuron bilateral antennal lobe receptor neuron adult neurosecretory neuron adult peptidergic neuron antennal basiconic sensillum ab4 adult olfactory receptor neuron Or56a VFB:FBbt_00067063 DoOR:Or56a adult olfactory receptor neuron Or56a Adult olfactory receptor neuron (ORN) that expresses Or56a and Or33a (Stensmyr et al., 2012). Its dendrite transduces signals from antennal basiconic sensillum ab4 and it detects geosmin (via the Or56a receptor), which indicates the presence of harmful microbes (Stensmyr et al., 2012). Its axon innervates the DA2 glomerulus in the ipsilateral antennal lobe, then crosses the midline via the antennal commissure to innervate the contralateral antennal lobe glomerulus DA2 (Stocker et al., 1990; Stensmyr et al., 2012). It expresses sNPF (Carlsson et al., 2010). It develops from an Nab precursor (Benton et al., 2025). There are approximately 20 of these cells on each side (Benton et al., 2025). fly_anatomy.ontology FBbt:00067063 adult olfactory receptor neuron Or56a/33a ORN_DA2 DoOR:ab4B adult ORN Or56a adult olfactory receptor neuron Or33a ORN ab4B DoOR:Or33a adult ORN Or56a/33a adult olfactory receptor neuron DA2 ORN (Or56a) FlyBrain_NDB:10409 ORN_DA2 adult ORN Or33a