Dickman J D, Fang Q
Department of Surgery (Otolaryngology), University of Mississippi Medical Center, Jackson 39216, USA.
J Comp Neurol. 1996 Mar 25;367(1):110-31. doi: 10.1002/(SICI)1096-9861(19960325)367:1<110::AID-CNE8>3.0.CO;2-6.
The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar afferents projected throughout the cochlear nuclei, to the dorsolateral regions of the cerebellar nuclei, and to lateral regions of the superior, lateral, medial, and descending vestibular nuclei.
利用神经示踪化合物研究了鸽子是否存在前庭传入信息向中枢核神经元的差异分布。通过切断支配不同感受器器官的前庭神经的各个分支，并应用辣根过氧化物酶晶体、辣根过氧化物酶/霍乱毒素混合物或生物素化合物进行神经元摄取和运输，对支配各个半规管和耳石器官的传入纤维进行了离散追踪。随后观察了传入纤维及其在脑干和小脑中的终末分布。鸽子中枢神经系统中接受初级前庭输入的离散区域包括上、背外侧、腹外侧、内侧、下行和切线前庭核；A组和B组；中间、内侧和外侧小脑核；以及小结、蚓垂和旁绒球。一般来说，垂直半规管传入纤维大量投射到上、下行前庭核以及A组的内侧区域。观察到垂直半规管向前庭内侧核和外侧核的投射，但不太明显。水平半规管向前庭上核和下行核的投射比垂直半规管的投射更靠近中央。与垂直半规管纤维相比，水平半规管传入纤维向前庭内侧核和外侧核的投射更明显。支配椭圆囊和球囊的传入纤维通常终止于所有前庭核的外侧区域，这些区域与半规管的投射区域分开。此外，椭圆囊纤维投射到前庭核中与水平半规管终末场重叠的区域，而球囊传入纤维投射到接受垂直半规管纤维终末的区域。壶腹嵴传入纤维投射到整个耳蜗核、小脑核的背外侧区域以及上、外侧、内侧和下行前庭核的外侧区域。
