Straube Andreas, Scheuerer Werner, Robinson Farrel R, Eggert Thomas
Department of Neurology, University of Munich, 81377 Munich, Germany.
Ann N Y Acad Sci. 2009 May;1164:119-26. doi: 10.1111/j.1749-6632.2008.03734.x.
The caudal fastigial nucleus (cFN) is one of the main cerebellar areas involved in the control of eye movements. Lesions of this area cause hypermetria of ipsilateral saccades and hypometria of contralateral saccades, as well as cogwheel smooth pursuit. Most studies with nonhuman primates described this dysmetria with a change of the ratio target amplitude to saccade amplitude, whereas in cats this dysmetria was attributed to a static fixation error. The targeting of visually-guided saccades before and after 11 unilateral injections of the inhibitory transmitter muscimol into the caudal fastigial nucleus in 5 monkeys was analyzed. In one monkey, who had eye coils implanted in both eyes, the postsaccadic interocular alignment was also analyzed. The main result is that the dysmetria observed in nonhuman primates can be explained as a combination of (1) hypermetria of the ipsilateral horizontal saccade component, and (2) a horizontal static fixation error of about 1.2 deg toward the side of the lesion. The static postsaccadic alignment of both eyes was only slightly disturbed after unilateral injection. The results suggest that the dysmetria seen after muscimol inactivation of the cFN is due to two distinct processes: one causes a gain change, and the other causes the static fixation error. Unilateral lesions have only a slight influence on binocular postsaccadic alignment.
尾侧顶核（cFN）是参与眼球运动控制的主要小脑区域之一。该区域受损会导致同侧扫视运动幅度增大，对侧扫视运动幅度减小，以及齿轮样平稳跟踪。大多数针对非人灵长类动物的研究通过目标幅度与扫视幅度比值的变化来描述这种眼球运动失调，而在猫中，这种眼球运动失调被归因于静态注视误差。分析了5只猴子在向尾侧顶核单侧注射11次抑制性递质蝇蕈醇前后视觉引导扫视运动的靶向情况。在一只双眼植入眼线圈的猴子中，还分析了扫视运动后的眼间对齐情况。主要结果是，在非人灵长类动物中观察到的眼球运动失调可以解释为以下两种情况的组合：（1）同侧水平扫视运动成分幅度增大，以及（2）向病变侧大约1.2度的水平静态注视误差。单侧注射后，双眼的静态扫视运动后对齐仅受到轻微干扰。结果表明，蝇蕈醇使cFN失活后出现的眼球运动失调是由两个不同的过程引起的：一个导致增益变化，另一个导致静态注视误差。单侧病变对双眼扫视运动后对齐的影响很小。
