Figure 4.

Tuning of DNOVS2 to a rotation-like optic flow around a longitudinal body axis. The responses of DNOVS2 to clockwise rotational-like optic flow at seven different monitor positions, each representing a different axis of rotation, is shown. This results in seven different axis of rotation, with angular separations from the midline: −42°, −22°, −12°, 0°, 12°, 22°, and 42°. Clockwise rotation around a longitudinal axis (0°) elicited the strongest response in DNOVS2. The measured response is significantly stronger than the arithmetic sum of the individual components. In contrast, the response to a rotation around an axis at 42° to the right is significantly less than the expected one. The clockwise, rotatory stimulus corresponds to a counterclockwise rotation as egomotion (indicated by the arrows). Data represent the mean ± SEM from n number of flies for each axis as follows: −42° (n = 4); −22° (n = 3); −12° (n = 7); 0° (n = 3); 12° (n = 3); 22° (n = 4); and 42° (n = 8).