Figure 7.

Object-induced response changes. Responses to straight flight sequences. The fly crossed the virtual flight arena parallel to and at equal distance from the side walls and the floor. A vertical cylindrical object (4 mm) was placed at a small distance from the flight trajectory. (A–C) Position-dependent response traces of FD1 (A), HSE (B), and vCH (C) while passing the object at 1 m/s in the small arena (cB) for one texture condition. Response traces without object are plotted in black, and those with object, in red. Position 0 is defined as the fly's position on the trajectory with the object at 90° in the lateral visual field. The yellow bar marks a flight interval of 30 mm length where the moves were through the most sensitive part of the cells' receptive field. (D–F) The median, quartiles, and range of responses with object (left) and without object (right) are shown as averaged over the 30 mm interval across the two velocities, the four textures and both arena sizes to assess whether the object can lead to larger responses than the background for a wider range of conditions. Model responses of FD1 (D), HSE (E), and vCH (F). (G–I) Object-induced response changes induced by a velocity of 0.5 m/s (left) and 1 m/s (right) as averaged over the 30 mm interval and normalized to responses in the same interval but without object. The object-induced response changes of FD1 (G), HSE (H), and vCH (I) are given separately for each texture condition (red dots) and averaged over all texture conditions (blue dots). The object-induced response changes were normalized to the corresponding mean responses generated without object.