Multiple time scales of adaptation allow cones to encode the inputs created by visual exploration of natural scenes

Primates explore their visual environment by making frequent saccades, discrete and ballistic eye movements that direct the fovea to specific regions of interest. Saccades produce large and rapid changes in input. The magnitude of these changes and the limited signaling range of visual neurons means that effective encoding requires rapid adaptation. Here, we explore how cone photoreceptors maintain sensitivity under these conditions. Adaptation makes cone responses to naturalistic stimuli highly nonlinear and dependent on stimulus history. Such responses cannot be explained by linear or linear-nonlinear models but are well explained by a biophysical model of phototransduction with fast and slow adaptational mechanisms. The resulting model can predict cone responses to a broad range of stimuli and enables the design of stimuli that elicit specific (e.g. linear) cone photocurrents. These advances will provide a foundation for investigating the contributions of cones and post-cone processing to visual function.