Fig. 1. Closed-loop feedback flight simulator. (A) The animals were placed in the centre of the simulator and modulated their wing stroke amplitudes in response to visual stimuli. An infra-red light cast shadows of the wings on a wing stroke analyser and an infra-red camera tracked the wings for calibration. Schematics not to scale. (B–D) Patterns displayed inside the simulator. (E) Output of a 1-D, 72-receptor-wide model of the fly's elementary motion detector (EMD) to rotation of a 24° spatial wavelength stripe pattern (M. Mronz and F.-O. Lehmann, manuscript submitted for publication). Dark grey areas indicate 100 (±125 deg. s^–1) and light grey areas 50% (±390 deg. s^–1) response threshold. L, left eye; R, right eye.