1. Olfactory sensory neuron population expansions influence projection neuron adaptation and enhance odour tracking.
- Author
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Takagi S, Sancer G, Abuin L, Stupski SD, Roman Arguello J, Prieto-Godino LL, Stern DL, Cruchet S, Álvarez-Ocaña R, Wienecke CFR, van Breugel F, Jeanne JM, Auer TO, and Benton R
- Subjects
- Animals, Drosophila physiology, Smell physiology, Adaptation, Physiological, Olfactory Pathways physiology, Species Specificity, Morinda, Female, Behavior, Animal physiology, Biological Evolution, Odorants, Olfactory Receptor Neurons physiology, Drosophila melanogaster physiology
- Abstract
The evolutionary expansion of sensory neuron populations detecting important environmental cues is widespread, but functionally enigmatic. We investigated this phenomenon through comparison of homologous olfactory pathways of Drosophila melanogaster and its close relative Drosophila sechellia, an extreme specialist for Morinda citrifolia noni fruit. D. sechellia has evolved species-specific expansions in select, noni-detecting olfactory sensory neuron (OSN) populations, through multigenic changes. Activation and inhibition of defined proportions of neurons demonstrate that OSN number increases contribute to stronger, more persistent, noni-odour tracking behaviour. These expansions result in increased synaptic connections of sensory neurons with their projection neuron (PN) partners, which are conserved in number between species. Surprisingly, having more OSNs does not lead to greater odour-evoked PN sensitivity or reliability. Rather, pathways with increased sensory pooling exhibit reduced PN adaptation, likely through weakened lateral inhibition. Our work reveals an unexpected functional impact of sensory neuron population expansions to explain ecologically-relevant, species-specific behaviour., (© 2024. The Author(s).)
- Published
- 2024
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