Abstract

The contrast response functions of cat and monkey visual cortex neurons reveal two important nonlinearities (expansive exponents and contrast gain control) that can have beneficial effects on stimulus selectivity. As contrast increases, response generally increases rapidly with a power function exponent greater than 1.0 (the average is 2.5), and then saturates; further, when measured at different spatial frequencies, the contrast response functions shift vertically (on log–log coordinates) indicating a contrast-set gain mechanism.¹

© 1991 Optical Society of America