Fig. 1. A schematic view of the visual arena. The arena had a circumference of 160 rows and a height of 24 rows of LEDs with 24 columns removed at the up- and downwind ends to allow smooth airflow over the fly. Flies were glued to a steel pin, positioned between two magnets, allowing rotation around the functional yaw axis. A camera positioned below the tunnel visualized the fly at 100 Hz through a hole in the center of a set of ring magnets.