NSCI 201 Chapter Notes - Chapter 20: Cranial Nerve Nucleus, Medial Rectus Muscle, Extraocular Muscles
8 May 2016
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Smooth pursuit: slower tracking motions to keep moving stimulus on fovea! Saccadic: rapid, ballistic movements that change point of xation! Vestibulo-ocular, optokinetic: stabilization to compensate for head/ body movements! Vergence movements: align fovea of each eye to targets at different distances! This setup ensures that image is always projected on fovea after a while, image actually disappears due to receptor fatigue, and editing. We"re always looking at things even if we don"t feel like we are eyes make tiny movements and saccades to track background imagery. Six pairs of extra-ocular muscles contribute to vertical and horizontal eye movements! Recall: lateral and medial recti move eyes in medial-lateral plane. These movements are also called adduction (toward nose), abduction (towards temples) also involved in vergence movements. Vertical movements are due to superior and inferior recti. Torsional movements due to superior and inferior obliques. Intorsion: rotation of eye from top towards nose; extorsion (away from nose)!
