Functional Impact of Sensory Neuron Compartmentalization on Olfactory Behavior
Across animal species, many primary sensory neurons are compartmentalized in specialized structures, such as the olfactory sensory hairs (sensilla) of insects. In Drosophila, compartmentalization of olfactory receptor neurons (ORNs) allows grouped neurons to functionally interact through direct electrical interactions such that strong activation of one ORN can inhibit the olfactory response of its neighbor. However, the functional impact of lateral inhibition on odor-guided behavior remains underexplored. Using thermogenetic behavioral assays, I determine that grouped ORNs in the ac4 sensillum mediate courtship behaviors of opposing valence. In addition, I find that in the oviposition-mediating ab4 sensillum, valence opponency also applies in a courtship context. Furthermore, I conduct pheromone-perfuming experiments and find that detection of antagonistic cues by neighboring ORNs in the at4 sensillum modulates courtship behaviors to a greater degree than detection of antagonistic cues by the non-neighboring at4A and at1 neurons. Taken together, these findings indicate that lateral inhibition in individual sensillum can regulate behavioral responses to countervailing olfactory cues. Thus, this study brings insight into the functional significance of sensory neuron compartmentalization.