Meek J, Nieuwenhuys R, Elsevier D
J Comp Neurol. 1986 Mar 15;245(3):342-58. doi: 10.1002/cne.902450305.
The present paper is devoted to the extrinsic connections of lobe C3 of the highly differentiated corpus cerebelli of the electric fish Gnathonemus petersi. For this purpose, HRP injections or gels were placed in distinct parts of lobe C3 or its peduncle, in the pretectal region, and in the eye. Moreover, the presence of serotonin and tyrosine-hydroxylase was studied with immunohistochemical methods. The afferent connections of the rostral and caudal part of lobe C3 appear to differ considerably. Although both parts receive comparable projections from two pretectal nuclei (termed nucleus geniculatus and dorsal anterior pretectal nucleus) and the inferior olive, they receive projections from different parts of the nucleus lateralis valvulae, a large cell mass in the midbrain tegmentum, composed of small, tightly packed neurons. The caudal part of lobe C3 receives a projection from the most rostromedial cap of cells of this nucleus, whereas the rostral cap of lobe C3 receives efferents from the neighboring, more caudolateral, zone of cells of the nucleus lateralis valvulae. The caudal part of lobe C3, but not its rostral part, receives an additional projection from a nucleus in the isthmus region, termed nucleus Q. This nucleus sends a collateral projection to the torus longitudinalis. The efferents of both parts of lobe C3 project to slightly different parts of the midbrain tegmentum and the nucleus reticularis superior, and originate at least partly from eurydendroid cells. None of the nuclei and fiber tracts labeled could be shown to contain serotonin or catecholamines. The connections of lobe C3, as revealed by the present study, are compared with those of other parts of the mormyrid cerebellum and with those of the corpus cerebelli of other teleosts, with emphasis on the homology and functional significance of pretectocerebellar connections, the topical order in the cerebellar projections of the nucleus lateralis valvulae, and the relations between the cerebellum and torus longitudinalis. Comparison of the cerebellar connections in different teleostean species suggests that the strong development and the considerable differentiation of the cerebellum of mormyrids are related to at least two types of changes in the extrinsic connections, i.e.: a redistribution or parcelling of connections and the development of connections specific for mormyrids.
本文致力于研究电鱼彼得氏裸臀鱼高度分化的小脑C3叶的外在连接。为此，将辣根过氧化物酶注射剂或凝胶置于C3叶或其脚的不同部位、顶盖前区和眼睛中。此外，还用免疫组织化学方法研究了5-羟色胺和酪氨酸羟化酶的存在情况。C3叶的头端和尾端部分的传入连接似乎有很大差异。虽然这两个部分都从两个顶盖前核（称为外侧膝状体核和顶盖前背侧核）和下橄榄核接受类似的投射，但它们从外侧瓣膜核的不同部分接受投射，外侧瓣膜核是中脑被盖中的一个大细胞团，由紧密排列的小神经元组成。C3叶的尾端部分从该核最头内侧的细胞帽接受投射，而C3叶的头端帽接受来自外侧瓣膜核相邻的、更靠尾外侧的细胞区的传出纤维。C3叶的尾端部分，而不是其头端部分，从峡部区域的一个核（称为Q核）接受额外的投射。这个核向纵纹隆起发出侧支投射。C3叶两个部分的传出纤维投射到中脑被盖和上网状核的略有不同的部位，并且至少部分起源于多形细胞。所标记的核和纤维束均未显示含有5-羟色胺或儿茶酚胺。本研究揭示的C3叶的连接与裸臀鱼小脑其他部分的连接以及其他硬骨鱼小脑的连接进行了比较，重点在于顶盖小脑连接的同源性和功能意义、外侧瓣膜核小脑投射的局部顺序以及小脑与纵纹隆起之间的关系。不同硬骨鱼物种小脑连接的比较表明，裸臀鱼小脑的强烈发育和显著分化与外在连接的至少两种变化有关，即：连接的重新分布或划分以及裸臀鱼特有的连接的发育。
