Contrast adaptation and sensitization

Not only do natural scenes span an enormous range of luminance, but they can also vary in contrast 10,000-fold from one region to another within the same scene. Yet, as we saccade to these different contrast regions, we can discern details immediately, with no apparent processing delay. Contrast adaptation allows visual neurons to rapidly adjust their dynamic range to match that of the visual input, and it begins within the retina. This chapter covers the known mechanisms of contrast adaptation in the vertebrate retina and a related, more recently discovered computation called contrast sensitization.