title: Genetic dissection reveals two separate retinal substrates for polarization vision in Drosophila.
abstract: BACKGROUND
  Linearly polarized light originates from atmospheric scattering or surface reflections and is perceived by insects, spiders, cephalopods, crustaceans, and some vertebrates. Thus, the neural basis underlying how this fundamental quality of light is detected is of broad interest. Morphologically unique, polarization-sensitive ommatidia exist in the dorsal periphery of many insect retinas, forming the dorsal rim area (DRA). However, much less is known about the retinal substrates of behavioral responses to polarized reflections.
  
  
  CONCLUSIONS
  Drosophila exhibits polarotactic behavior, spontaneously aligning with the e-vector of linearly polarized light, when stimuli are presented either dorsally or ventrally. By combining behavioral experiments with genetic dissection and ultrastructural analyses, we show that distinct photoreceptors mediate the two behaviors: inner photoreceptors R7+R8 of DRA ommatidia are necessary and sufficient for dorsal polarotaxis, whereas ventral responses are mediated by combinations of outer and inner photoreceptors, both of which manifest previously unknown features that render them polarization sensitive.
  
  
  CONCLUSIONS
  Drosophila uses separate retinal pathways for the detection of linearly polarized light emanating from the sky or from shiny surfaces. This work establishes a behavioral paradigm that will enable genetic dissection of the circuits underlying polarization vision.
authors.affiliation: Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Mathias F
authors.initials: MF
authors.lastname: Wernet
authors.forename: Mariel M
authors.initials: MM
authors.lastname: Velez
authors.forename: Damon A
authors.initials: DA
authors.lastname: Clark
authors.forename: Franziska
authors.initials: F
authors.lastname: Baumann-Klausener
authors.forename: Julian R
authors.initials: JR
authors.lastname: Brown
authors.forename: Martha
authors.initials: M
authors.lastname: Klovstad
authors.forename: Thomas
authors.initials: T
authors.lastname: Labhart
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Clandinin
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004330:Drosophila / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D034281:Dynamins / Q000235:genetics; D005260:Female; D008027:Light; D008297:Male; D009799:Ocular Physiological Phenomena; D009949:Orientation; D054799:Phospholipase C beta / Q000235:genetics / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D014785:Vision, Ocular
chemical_list: D029721:Drosophila Proteins; C468371:NorpA protein, Drosophila; D054799:Phospholipase C beta; D034281:Dynamins