Sensory Neuron-Derived Eph Regulates Glomerular Arbors and Modulatory Function of a Central Serotonergic Neuron

Olfactory sensory neurons connect to the antennal lobe of the fly to create the primary units for processing odor cues,the glomeruli. unique amongst antennal-lobe neurons is an identified wide-field serotonergic neuron,the contralaterally-projecting,serotonin-immunoreactive deutocerebral neuron (csdn). the csdn spreads its termini all over the contralateral antennal lobe,suggesting a diffuse neuromodulatory role. a closer examination,however,reveals a restricted pattern of the csdn arborization in some glomeruli. we show that sensory neuron-derived eph interacts with ephrin in the csdn,to regulate these arborizations. behavioural analysis of animals with altered eph-ephrin signaling and with consequent arborization defects suggests that neuromodulation requires local glomerular-specific patterning of the csdn termini. our results show the importance of developmental regulation of terminal arborization of even the diffuse modulatory neurons to allow them to route sensory-inputs according to the behavioural contexts. © 2013 singh et al.