UC Riverside Undergraduate Research Journal

Taste is essential for humans and animals alike to evaluate food quality and make important decisionsabout food choice and intake. How complex brains process sensory information to produce behavioris an essential question in the field of sensory neurobiology. Currently, little is known about tastecircuits in the brain as compared to other sensory systems. Here, we used the common vinegar fly,Drosophila melanogaster, to explore the potential role of brain neurons labeled by a transgenic line(VT041723-GAL4) in producing “proboscis holding” behavior (extrusion of the mouthpart withoutwithdrawal). By utilizing the GAL4/UAS binary expression system, we expressed a heat-activatedcation channel (UAS-dTrpA1) in these brain neurons and artificially activated them by elevationof temperature, subsequently examining behavior in the heat-activated proboscis extension reflex(PER) assay. We found that activation of these neurons induced proboscis holding. Interestingly, theproboscis holding phenotype was sexually dimorphic. Male flies rarely showed proboscis holdingand those that did had shorter proboscis holding durations. On the other hand, both mated and virginfemales showed significantly more proboscis holding and had longer proboscis holding durationsthan male flies. Overall, we identified a subset of brain neurons labeled by the VT041723-GAL4 linethat controls a sexually dimorphic feeding response (proboscis holding) upon activation.