And yet it moves: perceptual illusions and neural mechanisms of pursuit compensation during smooth pursuit eye movements.

Pursuit eye movements are smooth rotations of the eye aimed at tracking moving objects. During pursuit, the visual system "compensates" for the eye movements, and transforms image movements captured by the eye from retinal to extra-retinal coordinates, for world-centered perception and action. When this function is impaired such as in schizophrenia, subjects misattribute retinal movements generated by their own eye movements to external sources. Surprisingly, even in healthy subjects pursuit compensation is incomplete, and results in illusory perception of motion. Neurophysiological, psychophysical and imaging studies elucidated many aspects of the neural substrates of visual processing during pursuit, including where and how in the cortex visual and non-visual signals interact to produce extra-retinal perception of motion. Here we review current understanding of motion processing in the visual cortex during pursuit and its relation to perception, from a broad perspective drawing from electrophysiology, fMRI, psychophysics and computational modeling. We discuss the experimental findings in the context of theories of pursuit compensation, and review some of the open questions in the field.