Enhancement of Flicker by Lateral Inhibition

Abstract

Sinusoidal modulation of illumination on the compound eye of the horseshoe crab, Limulus, produces a corresponding variation in the rate of discharge of optic nerve impulses. Increasing the area of illumination decreases the variation at low frequencies of modulation, but unexpectedly enhances—or "amplifies"—the variation at the intermediate frequencies to which the eye is most sensitive. Both effects must result from inhibition since it is the only significant lateral influence in this eye.