Figure 3.

Silencing or activating specific lamina neurons alters fly visual behavior in a virtual reality flight simulator. (A) A flying fly is suspended within an LED arena where the amplitude of each wingbeat is tracked by an optical detector. The difference between the two wingbeat amplitudes (ΔWBA) is proportional to yaw torque. For example, when the amplitude of the left wing-beat is greater than the right, the fly is attempting to steer to the right with clockwise torque. (B) Example flight steering responses (mean ± s.e.m.) to rotation of a full-field stimulus (90°/s corresponding to a temporal frequency of 3 Hz, left), and oscillation of a dark stripe (started at the center of the arena and oscillated between ± 37.5°, at 0.9 Hz, right). Silencing both L1 and L2 neurons with Kir2.1 abolishes behavioral responses to full-field and small-field motion stimuli. The space-time diagrams illustrate the luminance patterns displayed to the fly in the arena. (C) Behavioral tuning curves for two motion stimuli across all experimental genotypes. The results for each experimental line (or average of two lines), crossed to Kir2.1, are shown in red while the results for the control flies (see text for details) are shown in black. (top) Mean integrated steering responses (± s.e.m) to a full-field rotation stimulus (30° spatial period) at four temporal frequencies. (bottom) Fly responses to oscillation of a dark stripe at three frequencies. Tuning curves show the mean correlation (± s.e.m) between the stimulus position and the ΔWBA.