Meeting Abstract
Like other flies, Drosophila stabilize their gaze in response to both visual and inertial self-motion cues. The former are sensed by the fly’s compound eyes and the latter by the fly’s halteres, reduced hind wings that act as body rotation sensors. Gaze-stabilization reflexes mediated by each sense modality can operate independently of those mediated by the other sense, but previous work has shown that Drosophila flying on a tether (and thus generating no inertial self-motion cues) nonetheless exhibit deficits in visually-guided head movements when the halteres are ablated [Mureli et al. 2017]. Together with neurophysiological data from Calliphora [Huston and Krapp 2009], these works suggest that halteres modulate descending visual inputs to neck motoneurons. However, no study has characterized the influence of specific parameters of haltere kinematics on optomotor gaze in a flying, behaving animal. Using a tethered flight arena equipped with electromagnets, we induced motion in one of the halteres at one of several frequencies (or rendered it immobile) while showing the fly a periodic visual motion stimulus designed to a elicit yaw optomotor gaze responses. Flies with an immobilized haltere showed similar dynamics in their optomotor gaze-following versus intact controls, with the exception that their head movements were centered at a fixed offset from the body axis. Upon reintroduction of periodic haltere motion using the electromagnets, this offset was diminished. At the highest tested frequency, the offset was diminished significantly further, approaching that seen in matched intact controls. These findings suggest that haltere inputs spanning a wide frequency range are sufficient for supporting normal optomotor gaze responses in Drosophila.
