Meeting Abstract
Animals integrate multiple senses in order to understand the body’s relation to its surroundings. Flies use visual and proprioceptive clues to detect body rotations during flight using their eyes and halteres (modified hind wings). With input from both of these sensors, flies can stabilize their gaze to minimize motion blur during body rotations. Stabilizing head movements are only observed during flight, suggesting that neuromodulation (for example, by the transmitter octopamine, which is upregulated in flight) may mediate this behavior. Here, we use genetic manipulations of Drosophila to determine octopamine’s role in modulating gaze. In tethered insects, octopamine is not necessary for spontaneous head movement. When flies are presented with widefield visual stimuli in the yaw axis, however, octopamine is necessary for producing a gaze stabilizing optomotor response where head movements are coordinated with the visual stimulus. Conversely, when tethered flies are rotated about the yaw axis, with or without visual stimuli, octopamine is not necessary for coordinated head movements during flight, but is necessary for coordinated head movement when not flying. During flight, the halteres oscillate and detect yaw rotation. Our results suggest that when flies are not flying and their halteres are still, they use other sensory organs to detect rotation, and these sensory organs are modulated by octopamine. Increasing octopamine concentrations did not restore optomotor responses, indicating that octopamine is not sufficient for initiating gaze stabilizing optomotor responses, and that active flight is needed as well. Additionally, these findings indicate that octopamine does not have a direct effect on the motor control of neck movement, but fosters head-visual coordination through its modulation of visual neurons.
