The role of areas MT and MST in coding of visual motion underlying the execution of smooth pursuit.

What is the main purpose of visual motion processing? One very important aspect of motion processing is definitively the generation of smooth pursuit eye movements. These eye movements avoid motion blur of moving objects which would obstruct the analysis of the objects' visual details. However, these eye movements can only be executed if there is a moving target. So there is a very close and inseparable relationship between smooth pursuit and motion processing. The hub for visual motion processing is situated in the middle temporal (MT) and medial superior temporal (MST) area. Despite the undoubted importance of these areas for the generation of smooth pursuit or goal-directed behavior in general, it is important to keep in mind that motion processing in addition serves perceptual purposes such as object recognition, structure-from-motion detection, scene segmentation, self-motion estimation and depth perception. This review focuses at the beginning on pursuit-related activity recorded from MT and MST, subsequently extends the view to goal-directed hand movements, and finally addresses the possible contributions of these areas to motion perception.