title: An Array of Descending Visual Interneurons Encoding Self-Motion in Drosophila.
abstract: The means by which brains transform sensory information into coherent motor actions is poorly understood. In flies, a relatively small set of descending interneurons are responsible for conveying sensory information and higher-order commands from the brain to motor circuits in the ventral nerve cord. Here, we describe three pairs of genetically identified descending interneurons that integrate information from wide-field visual interneurons and project directly to motor centers controlling flight behavior. We measured the physiological responses of these three cells during flight and found that they respond maximally to visual movement corresponding to rotation around three distinct body axes. After characterizing the tuning properties of an array of nine putative upstream visual interneurons, we show that simple linear combinations of their outputs can predict the responses of the three descending cells. Last, we developed a machine vision-tracking system that allows us to monitor multiple motor systems simultaneously and found that each visual descending interneuron class is correlated with a discrete set of motor programs.
  
  
  
  Most animals possess specialized sensory systems for encoding body rotation, which they use for stabilizing posture and regulating motor actions. In flies and other insects, the visual system contains an array of specialized neurons that integrate local optic flow to estimate body rotation during locomotion. However, the manner in which the output of these cells is transformed by the downstream neurons that innervate motor centers is poorly understood. We have identified a set of three visual descending neurons that integrate the output of nine large-field visual interneurons and project directly to flight motor centers. Our results provide new insight into how the sensory information that encodes body motion is transformed into a code that is appropriate for motor actions.
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195.|Neuroscience Institute, New York University School of Medicine, New York, New York 10016, and.
authors.forename: Marie P
authors.identifier: 0000-0003-4491-6996
authors.initials: MP
authors.lastname: Suver
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195.|Department of Bioengineering, California Institute of Technology, Pasadena, California 91125.
authors.forename: Ainul
authors.identifier: 0000-0003-2073-6659
authors.initials: A
authors.lastname: Huda
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195.
authors.forename: Nicole
authors.initials: N
authors.lastname: Iwasaki
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195.
authors.forename: Steve
authors.initials: S
authors.lastname: Safarik
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195, flyman@caltech.edu.|Department of Bioengineering, California Institute of Technology, Pasadena, California 91125.
authors.forename: Michael H
authors.identifier: 0000-0002-8587-9936
authors.initials: MH
authors.lastname: Dickinson
mesh_terms: D000818:Animals; D004330:Drosophila / Q000502:physiology*; D004525:Efferent Pathways; D005426:Flight, Animal / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*
keywords: ethology; flight; self-motion estimation; vision