43.4 Thursday, Jan. 5 Vision-based altitude control in freely flying Drosophila ZABALA, F.A.*; DICKINSON, M.H.; Univ. of Washington firstname.lastname@example.org
Insects are thought to achieve robust flight stability through the implementation of rapid sensory-motor reflexes. Specialized interneurons within their visual system detect unintended rotations and translations during flight and convey that information to motor circuits that generate compensatory changes in wing motion. Until recently, most investigations of sensory motor reflexes in Drosophila have utilized tethered animals, but such conditions are known to generate artifacts. Measuring the subtle changes in wing motion that are elicited by visual input in free flight requires both very high spatial and temporal resolution, and the ability to track a flying animal within a suitably large region of space. To this end, we have developed an arena in which we can present arbitrary visual stimuli to freely flying fruit flies, and record with high definition their behavioral responses using 3D high speed videography. As the insects traverse a small volume in the arena, a laser-based detector circuit triggers a moving visual pattern displayed on a cylindrical panorama of LEDs. By analyzing the open-loop responses of the animals to the visual motion, we are able to characterize with high accuracy the changes in wing and body motion that are elicited during visually-mediated compensatory flight reflexes. The high-throughput in our analysis is facilitated by implementation of automated tracking software that incorporates 3D kinematic measurements from an image-based visual hull, a parameterized generative model of the fly, and a Sigma-Point Kalman Filter for parameter estimation. In a preliminary study, we investigated the altitude control response, which we elicited by vertically displacing a horizontal grating on the walls of the flight chamber. When presented with this stimulus, flies adjust their wing motion to generate a syndirectional flight response, which can be interpreted as an attempt to minimize the slip of the pattern on their retina.