Anmo Kim, The Rockefeller University
Vision influences behavior, but ongoing behavior also modulates vision, from insects to primates. For example, we constantly move our eyes from one point to another, even as we view a static scene. These eye movements cause the whole visual image to shift on our retinas; yet we hardly notice they are happening. The same visual motion, if replayed, causes a strong sense of visual motion. Consistent with this behavioral observation, previous studies reported transient modulation of visual processing during rapid eye movements. However, the function and biophysical mechanisms of most such modulations remain unresolved. We investigated a function for behavioral modulations of visual processing in Drosophila by combining behavioral genetics, electrophysiology, and high-speed videography. We provide evidence that, via a genetic inactivation experiments, a set of motion-sensitive visual neurons regulate gaze-stabilizing head movements. We describe how, during flight turns, Drosophila perform a set of head movements that require silencing their gaze-stability reflexes along the primary rotation axis of the turn. Consistent with this behavioral requirement, we find pervasive motor-related inputs to the visual neurons, which quantitatively silence their predicted visual responses to rotations around the relevant axis while preserving sensitivity around other axes. This work proposes a function for a behavioral modulation of visual processing and illustrates how the brain can remove one sensory signal from a circuit carrying multiple related signals.