Exploring the role of a premotor cell type for active sensor control in Drosophila

PROJECT SUMMARY An animal’s nervous system enables it to detect and respond to stimuli to navigate its environment. To enhance sensory acquisition, animals can actively position sensors, altering how they extract information from the external world. However, active sensing, and movement in general, produces stimuli that feeds back onto these same sensory systems – requiring mechanisms for integrating predictive motor signals with externally-generated sensations. Despite the importance of these mechanisms for guiding coordinated behavior, the cellular and circuit basis of motor control and sensation during active movements are not fully understood. This proposal aims to determine how mechanosensory information controls motor output in the Drosophila antenna, an active sensor that can be passively deflected or actively positioned. Previous work shows that APN2, a class of antennal mechanosensory and motor center projection neurons, contributes to an afferent sensory pathway. However, my preliminary connectomics and optogenetic behavior data support that APN2 also lies presynaptic to antennal motor neurons, suggesting a role beyond mechanosensory afference. I hypothesize that APN2, as a premotor class of neurons receiving direct mechanosensory input, enable active antennal positioning via integration of sensory and higher-order motor signals. In Aim 1, I will use electrophysiology and quantitative behavior to characterize the activity of APN2 during different active and passive antennal movements. In Aim 2, I will measure the relative influence of sensory input on APN2 activity during behavior with electrophysiology and machine-learning assisted antennal tracking. By defining APN2’s role in antennal motor control, this proposal will uncover the functional logic of a sensory-motor circuit controlling an active sensor.