Pierrot-Deseilligny Charles
Service de Neurologie 1, Clinique Paul Castaigne, Hôpital de la Salpêtrière, Paris, France.
Handb Clin Neurol. 2011;102:319-31. doi: 10.1016/B978-0-444-52903-9.00018-2.
In the brainstem, lateral and vertical eye movements are controlled by separate structures, the former mainly in the pons and the latter in the midbrain. The abducens nucleus (VI) in the pons controls all ipsilateral eye movements, i.e., ipsilateral saccades as well as the horizontal vestibulo-ocular reflex (VOR). This nucleus contains the abduction motoneurons, but also the internuclear neurons involved in adduction, passing through the contralateral medial longitudinal fasciculus (MLF) before relaying in the third-nerve nucleus in the midbrain. Lesions affecting the abducens nucleus result in complete ipsilateral eye movement paralysis, and lesions damaging the MLF result in internuclear ophthalmoplegia, whereas an association of these two lesions leads to the "one-and-a-half" syndrome. Ipsilateral saccades are controlled by the ipsilateral paramedian pontine reticular formation located close to the sixth nucleus, whereas the ipsilateral VOR is controlled by the contralateral medial vestibular nucleus. Vertical eye movements are controlled by the third- and fourth-nerve nuclei in the midbrain. A lesion unilaterally affecting the third-nerve nucleus results in an ipsilateral third-nerve paralysis and a contralateral upgaze paralysis because of the decussation of the superior rectus motoneurons, at the level of the third-nerve nuclei. Vertical saccades are controlled by the rostral interstitial nucleus of the MLF (riMLF) located close to the third-nerve nucleus. Downward and upward saccade paralysis results from bilateral riMLF damage whereas upgaze paralysis usually results from a unilateral lesion affecting the region of the posterior commissure, suggesting that the suprareticular control of these two types of vertical saccade is distinct.
在脑干中，眼球的水平和垂直运动由不同的结构控制，前者主要在脑桥，后者在中脑。脑桥中的展神经核（VI）控制同侧所有眼球运动，即同侧扫视运动以及水平前庭眼反射（VOR）。该核包含外展运动神经元，也包含参与内收的核间神经元，这些核间神经元在中继至中脑的动眼神经核之前穿过对侧的内侧纵束（MLF）。影响展神经核的病变会导致同侧眼球运动完全麻痹，而损伤MLF会导致核间性眼肌麻痹，这两种病变同时出现则会导致“一个半”综合征。同侧扫视运动由位于靠近展神经核的同侧脑桥旁正中网状结构控制，而同侧VOR由对侧内侧前庭核控制。垂直眼球运动由中脑的动眼神经核和滑车神经核控制。单侧影响动眼神经核的病变会导致同侧动眼神经麻痹和对侧上视麻痹，这是因为上直肌运动神经元在动眼神经核水平交叉。垂直扫视运动由位于靠近动眼神经核的内侧纵束嘴侧间质核（riMLF）控制。双侧riMLF损伤会导致向下和向上扫视运动麻痹，而上视麻痹通常由单侧影响后连合区域的病变引起，这表明这两种垂直扫视运动的网状上控制是不同的。
