Selective integration of diverse taste inputs within a single taste modality

• Authors: Julia U Deere, Columbia University; Arvin A Sarkissian, Emory University; Meifeng Yang, Emory University; Hannah A Uttley, Columbia University; Nicole M Santana, Columbia University; Lam Nguyen, Emory University; Kaushiki Ravi, Emory University; Anita Devineni, Emory University
• Journal Title: eLife
• Volume: Volume 12
• Publisher: eLife Sciences Publications Ltd. | 2023-01-01
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.7554/eLife.84856
• Subjects: Biology, Neuroscience
• Keywords: D. melanogaster; feeding; neural circuits; neuroscience; sensory processing; taste; Animals; Taste; Drosophila melanogaster; Taste Perception; Drosophila; Brain

Abstract

A fundamental question in sensory processing is how different channels of sensory input are processed to regulate behavior. Different input channels may converge onto common downstream pathways to drive the same behaviors, or they may activate separate pathways to regulate distinct behaviors. We investigated this question in the Drosophila bitter taste system, which contains diverse bitter-sensing cells residing in different taste organs. First, we optogenetically activated subsets of bitter neurons within each organ. These subsets elicited broad and highly overlapping behavioral effects, suggesting that they converge onto common downstream pathways, but we also observed behavioral differences that argue for biased convergence. Consistent with these results, transsynaptic tracing revealed that bitter neurons in different organs connect to overlapping downstream pathways with biased connectivity. We investigated taste processing in one type of downstream bitter neuron that projects to the higher brain. These neurons integrate input from multiple organs and regulate specific taste-related behaviors. We then traced downstream circuits, providing the first glimpse into taste processing in the higher brain. Together, these results reveal that different bitter inputs are selectively integrated early in the circuit, enabling the pooling of information, while the circuit then diverges into multiple pathways that may have different roles.