Head movements quadruple the range of speeds encoded by the insect motion vision system in hawkmoths

Shane Windsor, Graham K Taylor

Research output: Contribution to journalArticle (Academic Journal)

1 Citation (Scopus)
209 Downloads (Pure)

Abstract

Flying insects use compensatory head movements to stabilize gaze. Like other optokinetic responses, these movements can reduce image displacement, motion and misalignment, and simplify the optic flow field. Because gaze is imperfectly stabilized in insects, we hypothesized that compensatory head movements serve to extend the range of velocities of self-motion that the visual system encodes. We tested this by measuring head movements in hawkmoths Hyles lineata responding to full-field visual stimuli of differing oscillation amplitudes, oscillation frequencies and spatial frequencies. We used frequency-domain system identification techniques to characterize the head ’s roll response, and simulated how this would have affected the output of the motion vision system, modelled as a computational array of Reichardt detectors. The moths ’ head movements were modulated to allow encoding of both fast and slow self-motion, effectively quadrupling the working range of the visual system for flight control. By using its own output to drive compensatory head movements, the motion vision system thereby works as an adaptive sensor, which will be especially beneficial in nocturnal species with inherently slow vision. Studies of the ecology of motion vision must therefore consider the tuning of motion-sensitive interneurons in the context of the closed-loop systems in which they function.

Original languageEnglish
Article number20171622
Number of pages9
JournalProceedings of the Royal Society B: Biological Sciences
Volume284
Issue number1864
Early online date4 Oct 2017
DOIs
Publication statusPublished - 11 Oct 2017

Keywords

  • Elementary motion detector
  • Eye movements
  • Flight control
  • Gaze stabilization
  • Head movements
  • Motion vision

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