Abstract
Eye movements are crucial for vision. Saccadic eye movements bring the line of sight to selected objects, and smooth pursuit maintains the line of sight on moving objects. A major potential obstacle to achieving accurate and precise saccadic or pursuit performance is the inevitable sensorimotor delay that accompanies the processing of the position or motion of visual signals. To overcome the deleterious effects of such delays, eye movements display a remarkable capacity to respond on the basis of predicted sensory signals. Behavioral and neurophysiological studies over the past several years have addressed the mechanisms responsible for predictive eye movements. This talk will review key developments, focusing on anticipatory smooth eye movements (smooth eye movements in the direction of the expected future motion of a target). Anticipatory smooth eye movements (a) can be triggered by high-level, symbolic cues that signal the future path of a target, and (b) are generated by neural pathways distinct from those responsible for maintained smooth pursuit. When the predictability of the target motion decreases, anticipatory smooth eye movements are not suppressed, but rather reflect expectations about the likely future path of the target estimated on the basis of the recent past history of motions. Comparable effects of expectations have been shown to apply to the temporal pattern of saccades. The pervasive influence of prediction on oculomotor control suggests that one of the more important benefits of the ability to generate predictions from either explicit cues or statistical estimates is to ensure accurate and timely oculomotor performance.