Schematic diagrams showing a hypothesis for signal processing operations and coordinate transformations underlying the generation of pursuit eye movements. The center panel uses green arrows to summarize the postulated flow of signals through the pursuit system.V1, Primary visual cortex; MT, middle temporal visual area; MST, medial superior temporal area; FPA, frontal pursuit area; DLPN, dorsolateral pontine nucleus. The center panel usesboxes to indicate signal processing operations and coordinate transformations. The three main boxes suggest a progression from retinal to spatial to muscle coordinates. Thefour boxes containing names of signal processing operations and anatomical areas indicate the postulated order of signal processing in the pursuit system. Theleft and right panels show how single-target and two-target stimuli would be processed according to the hypothesis in the center panel. The left panel shows processing for a single target moving obliquely at 45° right and up. The right panel shows processing for two targets moving purely rightward and upward. At each stage, the blue and red icons represent prelearning and postlearning representations, respectively, for right-decrease learning experiments. The top pairs oficons are meant to show population responses in V1 and MT, whereas the icons in the secondthrough fourth groups indicate the direction and magnitude of representations at downstream levels.