Neuroscientists, including myself, strive to learn the general principles on how the brain works, often using model organisms. However, model organisms are distantly related to each other as well as to humans, making it difficult to translate perspectives across species. I believe that comparative, cross-species approaches to elucidate how nervous systems adapt to confer animals with unique behaviors will be an effective complementary way to extract general principles of brain organization and function.

In this project,  we address the question of “How does sensory neuron number matter?” by leveraging the comparative framework. Sensory neuron number increase has been assumed to sensitize the central response and behavior, but this idea had not been experimentally tested. We compare the homologous olfactory circuits between Drosophila melanogaster and its close relative Drosophila sechellia, which underwent expansion of olfactory sensory neuron population detecting ecologically relevant cues. We combined genetic, molecular, neuroanatomical, neurophysiological, and neuroethological approaches and found out that sensory neuron number increase does not sensitize the central responses, in contrast to the long-held assumption. Rather, we found that it modulates olfactory habituation and enhances odor tracking behavior. 

For details, see the following publication:

Takagi S†*, Sancer G, Abuin L, Stupski SD, Arguello JR, Prieto-Godino LL, Stern DL, Cruchet S, Álvarez-Ocaña R, Wienecke CFR, van Breugel F, Jeanne JM, Auer TO†*, Benton R* (†: equal contribution, *: corresponding authors) “Olfactory sensory neuron population expansions influence projection neuron adaptation and enhance odour tracking”Nature Communications, 2024, Aug 15;15(1):7041. doi: 10.1038/s41467-024-50808-w PMID: 39147786