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Fig. 4. Effects of angular target speed on response amplitude and image blur.
(A,B) Mean response amplitudes
V of 7 male (A) and 7
female (B) photoreceptors to simulated target stimuli, plotted against angular
target speed
. The male response is larger than the female response and
demonstrates an optimum angular speed that increases with target size. (C,D)
Mean angular response width 
v of the same male (C) and
female (D) photoreceptors to simulated target stimuli, plotted against angular
target speed
. At low speeds, response widths are less than the widths
of the targets (indicated by dotted lines), especially in the male. At high
speeds, response width increases with speed (motion blur).