Henn V
Neurology Department, University Hospital Zürich, Switzerland.
Baillieres Clin Neurol. 1992 Aug;1(2):373-91.
Saccades and fast phases of optokinetic or vestibular nystagmus are rapid eye movements which are generated in the reticular formation of the brain stem. Palsies of rapid eye movement generation therefore always point towards an infratentorial lesion. Two cell assemblies are responsible for the generation of rapid eye movements: the PPRF, which triggers all rapid eye movements and in this sense plays an important coordinating role in addition to generating movements with a horizontal movement component, and the riMLF in the mesencephalon for movements which have a vertical or torsional direction component. As neurone populations are anatomically segregated according to their respective on-directions, focal lesions lead to the loss of rapid eye movements in particular directions (Table 2). Such palsies of rapid eye movement generation which are direction specific can be distinguished from dysmetria, which points towards a cerebellar lesion, or the difficulty to trigger a saccade to a particular target, which can involve cortical systems.
扫视以及视动性或前庭性眼球震颤的快相是快速眼球运动，由脑干网状结构产生。因此，快速眼球运动生成麻痹总是提示幕下病变。有两个细胞集合负责快速眼球运动的生成：脑桥旁正中网状结构（PPRF），它触发所有快速眼球运动，从这个意义上说，除了产生具有水平运动成分的运动外，还起着重要的协调作用；以及中脑的中介纵束旁核（riMLF），负责产生具有垂直或扭转方向成分的运动。由于神经元群体根据其各自的朝向在解剖学上是分开的，局灶性病变会导致特定方向的快速眼球运动丧失（表2）。这种特定方向的快速眼球运动生成麻痹可与指向小脑病变的辨距不良，或触发向特定目标的扫视困难相区分，后者可能涉及皮质系统。
