Visual Control of Walking Speed in Drosophila

An animal’s self-motion generates optic flow across its retina, and it can use this visual signal to regulate its orientation and speed through the world. While orientation control has been studied extensively in Drosophila and other insects, much less is known about the visual cues and circuits that regulate translational speed. Here, we show that flies regulate walking speed with an algorithm that is tuned to the speed of visual motion, causing them to slow when visual objects are nearby. This regulation does not depend strongly on the spatial structure or the direction of visual stimuli, making it algorithmically distinct from the classic computation that controls orientation. Despite the different algorithms, the visual circuits that regulate walking speed overlap with those that regulate orientation. Taken together, our findings suggest that walking speed is controlled by a hierarchical computation that combines multiple motion detectors with distinct tunings. [Display omitted] •Drosophila slows in response to visual motion to stabilize its walking speed•Slowing is tuned to the speed of visual stimuli•Walking speed modulation relies on T4 and T5 neurons•A model combining multiple motion detectors can explain the behavioral results During navigation, animals regulate both rotation and translation. Creamer et al. investigate how visual motion cues regulate walking speed in Drosophila. They find that orientation and walking speed are stabilized by algorithms with distinct tunings but employ overlapping circuitry.