title: Parallel neural pathways in higher visual centers of the Drosophila brain that mediate wavelength-specific behavior.
abstract: Compared with connections between the retinae and primary visual centers, relatively less is known in both mammals and insects about the functional segregation of neural pathways connecting primary and higher centers of the visual processing cascade. Here, using the Drosophila visual system as a model, we demonstrate two levels of parallel computation in the pathways that connect primary visual centers of the optic lobe to computational circuits embedded within deeper centers in the central brain. We show that a seemingly simple achromatic behavior, namely phototaxis, is under the control of several independent pathways, each of which is responsible for navigation towards unique wavelengths. Silencing just one pathway is enough to disturb phototaxis towards one characteristic monochromatic source, whereas phototactic behavior towards white light is not affected. The response spectrum of each demonstrable pathway is different from that of individual photoreceptors, suggesting subtractive computations. A choice assay between two colors showed that these pathways are responsible for navigation towards, but not for the detection itself of, the monochromatic light. The present study provides novel insights about how visual information is separated and processed in parallel to achieve robust control of an innate behavior.
authors.affiliation: Institute of Molecular and Cellular Biosciences (IMCB), University of Tokyo Tokyo, Japan ; Department of Neurobiology and Anatomy, University of Utah Salt Lake City, UT, USA.
authors.forename: Hideo
authors.initials: H
authors.lastname: Otsuna
authors.affiliation: Institute of Molecular and Cellular Biosciences (IMCB), University of Tokyo Tokyo, Japan ; Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University Halifax, NS, Canada.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Shinomiya
authors.affiliation: Institute of Molecular and Cellular Biosciences (IMCB), University of Tokyo Tokyo, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ito
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D010775:Photic Stimulation; D014157:Transcription Factors / Q000378:metabolism; D014795:Visual Pathways / Q000378:metabolism / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; C557617:GAL4 protein, Drosophila; D014157:Transcription Factors
keywords: Drosophila; color vision; higher visual center; phototaxis; wavelength-dependent