Figure 1.

The saccadic system hierarchy. At the lowest level are horizontal gaze centers—burst neurons in the paramedian pontine reticular formation (PPRF) and vertical gaze centers—burst neurons in the midbrain rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) which generate saccadic command to the extraocular muscles. Above the PPRF and riMLF level are the superior culliculus (SC), important for target selection and initiation of eye movement (supplemented also by cerebellum and the cortex). At the top of this hierarchy are the cortical areas: the frontal eye field (FEF), the parietal eye field (PEF) and the supplementary eye field (SEF) involved in recognition, inhibition, and decision about the movement.