Haroian A J, Massopust L C, Young P A
J Comp Neurol. 1981 Apr 1;197(2):217-36. doi: 10.1002/cne.901970205.
The purpose of this study was to determine the topographical organization of cerebellothalamic projections in the rat. Following stereotaxic injections of 3H-leucine or electrolytic lesions in the cerebellar nuclei, efferent fibers were observed to emerge from the cerebellum through two discrete routes. Fibers from the fastigial nucleus decussated within the cerebellum, formed the crossed ascending limb of the uncinate fasciculus, ascended in the dorsal part of the midbrain tegmentum, and entered the thalamus. Cerebellothalamic fibers from the interpositus and dentate nuclei coursed in the ipsilateral brachium conjunctivum, decussated in the caudal midbrain, and ascended to the thalamus via the crossed ascending limb of the brachium conjunctivum. Cerebellar terminations were observed in the intralaminar, lateral, and ventral tier thalamic nuclei as well as in the medial dorsal nucleus. Projections to the intralaminar nuclei were more pronounced from the dentate and posterior interpositus than from the anterior interpositus and fastigial nuclei. The lateral thalamic nuclei received a projection from the dentate and posterior interpositus nuclei while the fastigial nucleus projected to the medial dorsal nucleus. Within the rostral ventral tier nuclei fastigiothalamic terminations were localized in the medial parts of the ventral medial and ventral lateral nuclei, whereas dentatothalamic projections were concentrated in the lateral parts of the ventral medial nucleus and the medial half of the ventral lateral nucleus. Terminations from the posterior interpositus nucleus were observed ventrally and laterally within the caudal two-thirds of the ventral medial nucleus and throughout the ventral lateral nucleus, where they were densest in the lateral part of its lateral wing and within the central part of its cap. The anterior interpositus nucleus also projected to the central and lateral parts of the ventral lateral nucleus, but these terminations were considerably less dense than those from the posterior interpositus. A few fibers from the interpositus nuclei terminated in the medial part of the rostral pole of the ventral posterior nucleus. A prominent recrossing of cerebellothalamic fibers from the fastigial, posterior interpositus, and dentate nuclei occurred through the central medial nucleus of the internal medullary lamina. These terminated within the ipsilateral ventral lateral and intralaminar nuclei. These results show that each of the cerebellar nuclei project to the thalamus and that their terminations are topographically organized in the rostral ventral tier nuclei. The clustering of autoradiographic silver grains or terminal degeneration observed in the thalamic nuclei suggests a medial-to-lateral organization of this cerebellothalamic system.
本研究的目的是确定大鼠小脑丘脑投射的拓扑组织。在小脑核团立体定位注射³H-亮氨酸或进行电解损伤后，观察到传出纤维从脑干通过两条离散路径穿出。顶核的纤维在小脑内交叉，形成钩束的交叉上升支，在中脑被盖背侧上升，进入丘脑。来自间位核和齿状核的小脑丘脑纤维在同侧结合臂走行，在尾侧中脑交叉，并通过结合臂的交叉上升支上升至丘脑。在板内核、外侧核和腹侧层丘脑核以及背内侧核中观察到小脑终末。齿状核和后间位核向板内核的投射比前间位核和顶核更明显。外侧丘脑核接受来自齿状核和后间位核的投射，而顶核投射至背内侧核。在嘴侧腹侧层核内，顶核-丘脑终末位于腹内侧核和腹外侧核的内侧部分，而齿状核-丘脑投射集中在腹内侧核的外侧部分和腹外侧核的内侧半。在后间位核的终末见于腹内侧核尾侧三分之二的腹侧和外侧以及整个腹外侧核，在腹外侧核外侧翼的外侧部分和帽的中央部分最为密集。前间位核也投射至腹外侧核的中央和外侧部分，但这些终末比后间位核的终末密度低得多。来自间位核的少数纤维终止于腹后核嘴极的内侧部分。来自顶核、后间位核和齿状核的小脑丘脑纤维通过内髓板的中央内侧核发生明显的再交叉。这些纤维终止于同侧腹外侧核和板内核。这些结果表明，每个小脑核均投射至丘脑，且它们的终末在嘴侧腹侧层核中按拓扑方式组织。在丘脑核中观察到的放射自显影银粒或终末变性的聚集提示该小脑丘脑系统存在从内侧到外侧的组织方式。
