title: A hard-wired glutamatergic circuit pools and relays UV signals to mediate spectral preference in Drosophila.
abstract: Many visual animals have innate preferences for particular wavelengths of light, which can be modified by learning. Drosophila's preference for UV over visible light requires UV-sensing R7 photoreceptors and specific wide-field amacrine neurons called Dm8. Here we identify three types of medulla projection neurons downstream of R7 and Dm8 and show that selectively inactivating one of them (Tm5c) abolishes UV preference. Using a modified GRASP method to probe synaptic connections at the single-cell level, we reveal that each Dm8 neuron forms multiple synaptic contacts with Tm5c in the center of Dm8's dendritic field but sparse connections in the periphery. By single-cell transcript profiling and RNAi-mediated knockdown, we determine that Tm5c uses the kainate receptor Clumsy to receive excitatory glutamate input from Dm8. We conclude that R7s→Dm8→Tm5c form a hard-wired glutamatergic circuit that mediates UV preference by pooling ∼16 R7 signals for transfer to the lobula, a higher visual center.
authors: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Thangavel
authors: T
authors: Karuppudurai
authors: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Tzu-Yang
authors: TY
authors: Lin
authors: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Chun-Yuan
authors: CY
authors: Ting
authors: Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Randall
authors: R
authors: Pursley
authors: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Krishna V
authors: KV
authors: Melnattur
authors: Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Fengqiu
authors: F
authors: Diao
authors: Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Benjamin H
authors: BH
authors: White
authors: Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors: Lindsey J
authors: LJ
authors: Macpherson
authors: Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors: Marco
authors: M
authors: Gallio
authors: Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Thomas
authors: T
authors: Pohida
authors: Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Chi-Hon
authors: CH
authors: Lee
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D001931:Brain Mapping; D055253:Color Vision / Q000502:physiology* / Q000528:radiation effects; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology / Q000528:radiation effects; D049452:Green Fluorescent Proteins / Q000235:genetics; D055537:Light Signal Transduction / Q000502:physiology* / Q000528:radiation effects; D009415:Nerve Net / Q000502:physiology* / Q000528:radiation effects; D009907:Optometry; D017956:Photoreceptor Cells, Invertebrate / Q000145:classification / Q000502:physiology*; D034622:RNA Interference / Q000502:physiology; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D014795:Visual Pathways / Q000166:cytology* / Q000502:physiology / Q000528:radiation effects
chemical_list: D029721:Drosophila Proteins; D017470:Receptors, Glutamate; D049452:Green Fluorescent Proteins