Complex cell response depends on interslit spacing.

PSYCHOPHYSICAL studies have established that the human central visual system contains a large number of independent channels each of which responds maximally to a selectively oriented sine wave grating of a given spatial frequency and hardly at all to gratings of spatial frequencies differing by a factor of two1–4. Electrophysiological studies with moving sinusoidally modulated grating patterns have demonstrated that there exists a class of neurones in the striate cortex of cats5 and monkeys6 each member of which is maximally selective to a given spatial frequency and orientation.