Neuromuscular embodiment of feedback control elements in Drosophila flight

Abstract

While insects like Drosophila are flying, aerodynamic instabilities require that they make millisecond-timescale adjustments to their wing motion to stay aloft and on course. These stabilization reflexes can be modeled as a proportional-integral (PI) controller; however, it is unclear how such control might be instantiated in insects at the level of muscles and neurons. Here, we show that the b1 and b2 motor units—prominent components of the fly's steering muscles system—modulate specific elements of the PI controller: the angular displacement (integral, I) and angular velocity (proportional, P), respectively. Moreover, these effects are observed only during the stabilization of pitch. Our results provide evidence for an organizational principle in which each muscle contributes to a specific functional role in flight control, a finding that highlights the power of using top-down behavioral modeling to guide bottom-up cellular manipulation studies.

Wings of Change: aPKC/FoxP-dependent plasticity in steering motor neurons underlies operant selflearning inDrosophila

“…4B3). These results corroborate our hypothesis that the wing MNs identified above, specifically those that have been shown to be involved in generating OMRs (76,77), constitute a site of the plasticity mediating operant self-learning in Drosophila. We also tested whether it would be sufficient to test for optomotor asymmetry after training as a proxy measure for torque preference.…”

“…Although the MN innervating the third basalar muscle, b2, also expresses aPKC along the axon, we did not detect aPKC signal in axon terminals or active zones, and it does not show FoxP label, thus ruling out a function of b2 in aPKC/FoxP mediated operant self-learning. In contrast to b1 and b3, b2 firing is not linked to the wingbeat cycle; instead, it fires in bursts during turning maneuvers(82). Corroborating the conclusion that it is not involved in mediating operant selflearning, b2 is silent during straight flight, but it is likely involved in regulating body saccades(Heide, Götz, 1996), which are by themselves not relevant for controlling the heat in our experiments.…”