Research Summary

Understanding taste circuits and its modulation in Drosophila melanogaster

For all the animals, the sense of taste provides the ability to evaluate the quality of food sources. Food evaluation promotes ingestion of nutritious substances and discourages consumption of harmful substances. Food preference involves the peripheral taste system, but decision-making occurs in the central nervous system. I am interested in the gustatory system of Drosophila melanogaster to understand- how insects make the feeding decisions and the circuits involved? Drosophila can sense same taste stimuli as mammals, including sugars, water, salts, acids, alcohols and bitter. These compounds facilitate acceptance or avoidance behaviors. Although innate taste behaviors may be modified by learning and experience. The simplicity of ligands and behaviors, along with the molecular, genetic, calcium imaging and electrophysiological approaches, allows one to examine taste processing from sensory input to motor output in a system that can also be modified by learning. For greater understanding of peripheral and central taste coding my research will focus on identifying neuronal taste circuits in the brain that influence feeding behaviors. (2) Physiological factors that can modulate taste signals, which are not well understood in insects. The results of this study can be applied for insect pest control and reduced pathogen transmission by insects that impact human health.

Figure Legend: Schematic illustrating sweet taste processing in Drosophila: The axons of all peripheral gustatory receptor neurons terminate in the sub esophageal ganglion (SOG), the first relay for taste information in the fly brain. Labellar stimulation with sugars activates the sweet sensing Gustatory receptor Gr5a neurons (Green) that make synaptic connections with the first identified second order sweet gustatory projection neurons (NP1562 SGPNs-magenta) in the SOG. SGPNs axons relay sweet taste information to Antennal mechanosensory and motor center (AMMC) recently identified as an immediate higher-order processing center for sweet taste. Where and how the taste information for different taste modalities is conveyed from AMMC to higher brain center (mushroom body or Calyx) or back to SOG is not known.