Flexible Gating of Contextual Influences in Natural Vision

Identical sensory inputs can be perceived as strikingly different when embedded in distinct contexts. Neural responses to simple stimuli are also modulated by context, but the contribution of this modulation to the processing of natural sensory input is unclear. We measured surround suppression, a quintessential contextual influence, in macaque primary visual cortex with natural images. We found suppression strength varied substantially for different images. This variability was not well explained by existing descriptions of surround suppression, but it was predicted by Bayesian inference about statistical dependencies in images. In this framework, surround suppression was flexible: it was recruited when the image was inferred to contain redundancies, and substantially reduced in strength otherwise. Our results thus reveal a surprising gating of a basic, widespread cortical computation, by inference about the statistics of natural input.