Fig. 2. (A) The rotational gain (classic optomotor response) of flies in a rotating drum featuring vertical stripes. Gain was calculated as the mean angular velocity of the fly divided by the angular velocity of the pattern during a single trial. Values are means ± s.e.m. across all trials, where each trial consisted of 10 s of rotation with a given stripe width. N=4 flies, n=[123, 123, 123, 125, 130] trials. Stripe widths tested correspond to 1-5 pixels in our visual arena. (B) Error between real-time and post hoc saccade detection timing. Only events during which the real-time software detected a saccade within 15 ms after its true initiation time as calculated post hoc (gray box) were included for further analysis.