Caltech
“Olfaction in Drosophila through the lens of natural odors”
Natural odor space is structured by the biochemical processes of life, which generate characteristic mixtures of monomolecular volatiles in different odor sources. Animal brains interpret these complex natural mixtures and use this information to guide behaviors important for survival. I will describe recent progress in our understanding of how olfactory coding and behavior in the vinegar fly Drosophila reflects the statistical relationships of molecules as they occur in natural odor sources. First, we describe a new form of odor-selective lateral crosstalk between primary olfactory neurons that enables novel sensory transformations of olfactory input driven by odors characteristic of fermentation. We show how the spatiotemporal restructuring of these odor representations by lateral signal flow can support the context-dependent selection of the appropriate behavioral response to the important but complex environmental cue, carbon dioxide. Second, we provide evidence that neural representations of odors in the fly brain are reformatted in successive stages of olfactory processing to be increasingly organized around their relationships in natural sources, as compared to their relationships in terms of chemical properties. Finally, we provide an example of how the use of natural odors in experimental olfaction (relative to intense monomolecular stimuli that are typical), can lead to a re-interpretation of prior observations in olfactory neuroscience, in this case, the impact of odor experience in early life on olfactory behavioral plasticity. We discuss why these differences may be adaptive in the context of natural behavior. Together these results highlight new insights into olfaction that emerge from investigating the system in natural odor contexts.
Natural odor space is structured by the biochemical processes of life, which generate characteristic mixtures of monomolecular volatiles in different odor sources. Animal brains interpret these complex natural mixtures and use this information to guide behaviors important for survival. I will describe recent progress in our understanding of how olfactory coding and behavior in the vinegar fly Drosophila reflects the statistical relationships of molecules as they occur in natural odor sources. First, we describe a new form of odor-selective lateral crosstalk between primary olfactory neurons that enables novel sensory transformations of olfactory input driven by odors characteristic of fermentation. We show how the spatiotemporal restructuring of these odor representations by lateral signal flow can support the context-dependent selection of the appropriate behavioral response to the important but complex environmental cue, carbon dioxide. Second, we provide evidence that neural representations of odors in the fly brain are reformatted in successive stages of olfactory processing to be increasingly organized around their relationships in natural sources, as compared to their relationships in terms of chemical properties. Finally, we provide an example of how the use of natural odors in experimental olfaction (relative to intense monomolecular stimuli that are typical), can lead to a re-interpretation of prior observations in olfactory neuroscience, in this case, the impact of odor experience in early life on olfactory behavioral plasticity. We discuss why these differences may be adaptive in the context of natural behavior. Together these results highlight new insights into olfaction that emerge from investigating the system in natural odor contexts.