Dynamics of Motion Perception in the Desert Locust

The torque produced by the neck muscles of a locust mounted coaxially in an illuminated cylindrical striped drum follows small sinusoidal oscillations of the drum. Peak-to-peak oscillations of 0.03 degree (� 0.02 degree) at 0.1 cy/sec elicit measurable responses. Several features of this visual response to drum oscillation can be expected theoretically on the basis of a formal neural mechanism similar to that inferred by Hassenstein and Reichardt for constant-velocity motion perception in the bettle eye.