Langer T, Fuchs A F, Chubb M C, Scudder C A, Lisberger S G
J Comp Neurol. 1985 May 1;235(1):26-37. doi: 10.1002/cne.902350103.
To fulfill its putative role in short- and long-term modification of the vestibulo-ocular reflex, the flocculus of the cerebellum must send efferents to brainstem nuclei involved in the control of eye movements. In order to reveal the sites of these interactions, we determined the projections of the flocculus by autoradiography and orthograde transport of horseradish peroxidase in five rhesus macaques. Anterogradely labeled axons collected at the base of the injected folia and coursed caudally and medially between the middle cerebellar peduncle and the flocculus. They swept medially over the caudal surface of the middle cerebellar peduncle, over the dorsal surface of the cochlear nuclei, and then caudally along the lateral surface of the inferior cerebellar peduncle to pass over its dorsal surface in the cerebellopontine angle and terminate exclusively in the ipsilateral vestibular nuclei. Three contingents of axons could be differentiated. The axons of one group flowed caudally and medially into the y-group, which clearly received the densest floccular projection. Other, notably thicker, axons of this group continued rostrally and medially to terminate chiefly in the large-cell core of the superior vestibular nucleus. A second large contingent of thin axons streamed caudal and ventral to the y-group to form a compact tract adjacent to the lateral angle of the fourth ventricle and dorsal to the medial vestibular nucleus. Fibers from this tract (the angular bundle of Löwy) supplied a sizable projection to the rostral part of the medial vestibular nucleus and modest projection to the ventrolateral vestibular nucleus. A final group of fibers extended caudally and medially from the y-group in a plexus ventral to the dentate and interposed nuclei to terminate in the basal interstitial nucleus of the cerebellum (Langer, '85), a broadly distributed cerebellar nucleus on the roof of the fourth ventricle. The flocculus can affect vestibulo-ocular behavior only through these efferents to the vestibular nuclei and the basal interstitial nucleus of the cerebellum.
为了在短期和长期内对前庭眼反射进行调节，发挥其假定作用，小脑绒球必须向参与眼球运动控制的脑干核团发出传出纤维。为了揭示这些相互作用的位点，我们通过放射自显影和辣根过氧化物酶的顺行运输，在五只恒河猴中确定了绒球的投射。在注入小叶基部收集到的顺行标记轴突向尾侧和内侧走行，位于小脑中脚和绒球之间。它们向内侧扫过小脑中脚的尾侧表面、蜗神经核的背侧表面，然后沿小脑下脚的外侧表面向尾侧走行，在小脑脑桥角越过其背侧表面，仅终止于同侧前庭核。可以区分出三组轴突。一组轴突向尾侧和内侧流入y组，y组明显接受了最密集的绒球投射。该组中其他明显较粗的轴突继续向头侧和内侧走行，主要终止于上前庭核的大细胞核心。第二大组细轴突向尾侧和腹侧流向y组，在第四脑室外侧角附近和内侧前庭核背侧形成一个紧密的束。来自该束（洛伊角束）的纤维向前庭内侧核的头侧部分提供了相当大的投射，对前庭外侧核提供了适度的投射。最后一组纤维从y组向尾侧和内侧延伸，形成一个位于齿状核和间位核腹侧的丛，终止于小脑基底间质核（兰格，1985年），这是第四脑室顶广泛分布的小脑核。绒球只能通过这些向前庭核和小脑基底间质核的传出纤维来影响前庭眼反射行为。
