Almost all animals move and when they do, they alter the stream of information to their auditory, mechanosensory, visual, and other sensors. My work focuses on understanding two fundamental aspects of such active sensation. On the one hand, how do brains ignore those aspects of the changing sensory stream that are not informative for the task at hand. 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. I am using the fruit fly visual system 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 suggest that they would briefly abrogate the cells’ visual-sensory responses. 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, expected visual response, suggesting that they function as “efference copies”.
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 recently 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, direct visual attention, or increase acuity. We are currently perturbing the motoneurons that innervate the retinal muscles via optogenetics with the aim of informing the contributions of retinal movements to visually guided behaviors.