Evidence for joint encoding of motion and disparity in human visual perception

Electrophysiological recordings have established that motion and disparity signals are jointly encoded by subpopulations of neurons in visual cortex. However, the question of whether these neurons play a perceptual role has proven challenging and remains open. To answer this question we combined two powerful psychophysical techniques: perceptual adaptation and reverse correlation. Our results provide a detailed picture of how visual information about motion and disparity is processed by human observers, and how this processing is modified by prolonged sensory stimulation. We were able to isolate two perceptual components: a separable component, supported by separate motion and disparity signals, and an inseparable joint component, supported by motion and disparity signals that are concurrently represented at the level of the same neural mechanism. Both components are involved in the perception of stimuli containing motion and disparity information in line with the known existence of corresponding neuronal subpopulations in visual cortex.