In this case scenario, the difficulty begins with attempted right lateral gaze. The normal pathway is shown above. The cortex (frontal eye field) directs the opposite (right) horizontal gaze center to look right. The yoked movement of the two eyes is then orchestrated. The right abducens nucleus is stimulated to contract the right lateral rectus, while the stimulus is sent rostrally along the opposite (left) MLF (medial longitudianl fasciculus) to the left oculomotor nuclues in order to contract the left medial rectus in sync with the right lateral rectus. The cranial nerve nuclei III, IV, and VI are numbered and shown as the paired red-filled shapes. Click continue for more.