Active vision in flies

Dr. Lisa Fenk

Almost all a­­nimals move and when they do, they alter the stream of information to their auditory, mechanosensory, visual, and other sensors. We focus on understanding two fundamental aspects of such active sensation. On the one hand, how do brains ignore non-useful sensory consequences of motor acts, and on the other hand, and perhaps more remarkably, how do brains actively move their sensors to create sensory patterns of activity that better allow them to perceive the world. We are using the fruit fly to study both of these sensory challenges in a genetic model organism.

During fast flight turns we observe motor-related inputs to Drosophila visual cells whose properties whose properties are in line with efference copy signals. Rather than a wholesale shutdown of the visual system during flight turns, fly visual neurons are targeted by inputs that are precisely calibrated to abrogate each cell’s unique visual response.

In addition to suppressing the perception of self-generated visual motion during flight turns, flies also seem to purposefully generate visual motion in other circumstances. We found that Drosophila perform active retinal movements, akin to vertebrate eye movements, ranging from fixational microsaccades to an optokinetic reflex. These movements could serve to refresh the image, help distance estimation, or increase acuity.