Interactions Between Perception and Smooth Pursuit Eye Movements

When we see a moving object in our environment, our visual system analyzes and interprets this object’s trajectory. This motion analysis is very often then used to generate a smooth pursuit eye movement that tracks the object in order to stabilize its image on the retina. Smooth pursuit generation therefore requires visual motion signals. However, by stabilizing the retinal image of a moving object, smooth pursuit necessarily causes motion of the retinal images of stationary objects. Since such induced retinal motion does not dramatically affect pursuit – and more importantly, does not cause stationary objects to be perceived as moving – it is clear that depending on the context, similar sensory inputs can either dramatically influence both perception and pursuit or not at all. Recent research has suggested that such interaction between motion processing and smooth pursuit constitutes the core of a more general interaction between high-level perceptual integration and eye movements. Specifically, drive signals that move the eyes need not be purely retinal in nature, but can also be integrated based on disparate retinal motion directions. Moreover, ongoing motor commands themselves are used not only to cancel motion percepts of stable objects, but also to perceptually disambiguate spatial relationships between sensory features of visual objects. These results suggest that bidirectional interactions between perception and action allow maximum flexibility in generating coherent percepts of our environment – and associated actions on this environment.