Fig. 5. A hypothetical scheme for horizontal smooth pursuit. A hypothetical anatomic scheme for smooth pursuit eye movements. Signals encoding retinal image motion pass via the lateral geniculate nucleus (LGN) to striate cortex (V1), and extrastriate areas. MT (V5), middle temporal visual area; MST, medial superior temporal visual area; PP, posterior parietal cortex; FEF, frontal eye fields; SEF, supplementary eye fields. The nucleus of the optic tract (NOT) and accessory optic system (AOS) receive visual motion signals from the retina but also from extrastriate cortical areas. Cortical areas concerned with smooth pursuit project to the cerebellum via pontine nuclei, including the dorsolateral pontine nuclei (DLPN). The cerebellar areas concerned with smooth pursuit project to ocular motor neurons via fastigial, vestibular, and y-group nuclei; the pursuit pathway for fastigial nucleus efferents has not yet been defined. The NOT projects back to LGN. The NOT and AOS may influence smooth pursuit through their projections to the pontine nuclei, and indirectly, via the inferior olive. (Adapted from Leigh RJ, Zee DS: The Neurology of Eye Movements, 3rd ed. Oxford University Press, New York, 1999.)