Kuruvilla A, Sitko S, Schwartz I R, Honrubia V
Laryngoscope. 1985 Jun;95(6):692-707. doi: 10.1288/00005537-198506000-00012.
The central projections of the vestibular end organs in the bullfrog Rana calesbeiana were analyzed by using horseradish peroxidase labeling of the primary vestibular afferents. Separate extracellular injections were made of the anterior branch, the posterior branch, the ampullary nerve of each of the three semicircular canals, and the branch to the saccule. The anterior and posterior branches of the bullfrog eighth nerve, each containing both vestibular and auditory fibers, merge and enter the brain stem as a single nerve root. The thin caliber fibers of the anterior branch enter the brain stem on the ventral-posterior aspect of the nerve and immediately divide dichotomously into ascending (rostral) and descending (caudal) branches. The thick caliber fibers of the anterior branch enter the brain stem on the ventral-anterior aspect of the eighth nerve and traverse medially into the alar plate before dividing into ascending and descending branches. The primary afferent fibers of the vestibular nerve innervate an ipsilateral area of the brain stem which extends caudally from the rhombencephalon at the level of the twelfth nerve nucleus and rostrally up to and including the cerebellar nucleus and the cerebellum. The following vestibular nuclei can be identified by the fact that they receive primary vestibular afferents: the ventral vestibular nucleus, medial vestibular nucleus, descending vestibular nucleus, superior vestibular nucleus, and cerebellar nucleus. The dorsal (acoustic) nucleus, which receives primary auditory input, also receives afferents from the saccule. In addition to these nuclei, the cerebellum and the reticular formation receive significant primary input from the various vestibular receptors. The primary vestibulo-cerebellar fibers terminate mainly among the granular cells of the lobus auricularis and of the corpus cerebelli on the ipsilateral side. Each of the three semicircular canals projects into the cerebellum, while no such projection was observed in the saccular nerve preparations. Fibers from each of the three semicircular canals project to all of the vestibular nuclei. Heavily labeled large neurons, presumably vestibular efferents, are seen in the ipsilateral reticular formation, adjacent to the seventh motor nucleus.
通过对初级前庭传入神经进行辣根过氧化物酶标记，分析了牛蛙（牛蛙）前庭终器的中枢投射。分别对三个半规管的前支、后支、壶腹神经以及球囊分支进行了细胞外注射。牛蛙第八神经的前支和后支都包含前庭纤维和听觉纤维，它们合并后作为单一神经根进入脑干。前支的细纤维在神经的腹后侧进入脑干，并立即二分法分为升支（向头端）和降支（向尾端）。前支的粗纤维在第八神经的腹前侧进入脑干，并向内侧穿过进入翼板，然后再分为升支和降支。前庭神经的初级传入纤维支配脑干的同侧区域，该区域从第十二神经核水平的菱脑向尾端延伸，向头端一直延伸到包括小脑核和小脑。通过它们接受初级前庭传入神经这一事实，可以识别出以下前庭核：腹侧前庭核、内侧前庭核、降侧前庭核、上侧前庭核和小脑核。接受初级听觉输入的背侧（听觉）核也接受来自球囊的传入神经。除了这些核，小脑和网状结构还从各种前庭感受器接受大量的初级输入。初级前庭小脑纤维主要终止于同侧耳叶和小脑体的颗粒细胞之间。三个半规管中的每一个都投射到小脑中，而在球囊神经制剂中未观察到这种投射。三个半规管中的每一个的纤维都投射到所有前庭核。在同侧网状结构中，靠近第七运动核处可见大量标记的大神经元，推测为前庭传出神经。
