A functional angle on some after-effects in cortical vision

The question of how our brains and those of other animals code sensory info rmation is of fundamental importance to neuroscience research. Visual illus ions offer valuable insight into the mechanisms of perceptual coding. One s uch illusion, the tilt after-effect (TAE), has been studied extensively sin ce the 1930s: yet a full explanation of the effect has remained elusive. He re, we put forward an explanation of the TAE in terms of a functional role for adaptation in the visual cortex. The proposed model accounts not only f or the phenomenology of the TAE, but also for spatial interactions in perce ived tilt and the effects of adaptation on the perception of direction of m otion and colour. We discuss the implications of the model for understandin g the effects of adaptation and surround stimulation on the response proper ties of cortical neurons.