Cheek M D, Rustioni A, Trevino D L
J Comp Neurol. 1975 Nov 1;164(1):31-46. doi: 10.1002/cne.901640104.
The existence of a cerebellar projection from the dorsal column nuclei (gracile and cuneate nuclei, DCN) has been proposed on electrophysiological grounds but questioned when studied with neuroanatomical techniques. The retrograde transport of horseradish peroxidase (HRP) has been used for the present study and provides anatomical evidence of a DCN-cerebellar pathway. In adult cats, 1 to 6 mul of 30% HRP were injected in pars intermedia of the anterior lobe (lobules IV-V), in paramedial lobule and in vermis of the anterior (lobules IV-V) and of the posterior lobe (lobule VII). After survival of 24 to 48 hours, all animals were perfused with a double aldehyde mixture and serial 40 mu sections through the medulla oblongata were incubated for visualization of HRP. In all cases, medullary nuclei known to project to the injected cortical regions of the cerebellum contained HRP-positive neurons mainly ipsilateral to the injection (e.g., external cuneate nucleus) or mainly contralateral to it (e.g., inferior olivary complex). Following ipsilateral injections in either the paramedian lobule or the pars intermedia, HRP-positive neurons in the cuneate nucleus were concentrated in its rostral portion where multipolar cells with radiating dendrites predominate. In contrast, none of the clusters region, in the caudal part of the cuneate nucleus, displayed HRP-positive granules. In cases in which the anterior vermis was injected a few labelled cells were present in the rostral part of the gracile nucleus but not in the clusters region of this nucleus. No labelling of DCN neurons was evident after posterior vermis injection. To compare the distribution of cells contributing to the DCN-cerebellar pathway with that of thalamic relay cells in the DCN, 0.5 to 3 mul of 30% HRP were injected in the nucleus ventralis posterolateralis of the thalamus in another series of cats. Contralateral to the thalamic injection, labelled cells were concentrated in the clusters region of the gracile and cuneate but rostrally in these nuclei they were scattered among unlabelled neurons. The preferential location in the DCN of cells which project to the cerebellum and of cells which project to the thalamus stresses the heterogeneous organization of these nuclei along the rostrocaudal axis. Further, the results indicate that regions of the DCN which have been distinguished on the basis of cytoarchitectonics (Kuypers and Tuerk, '64) and of afferents (Rustioni, '73, '74) differ also in their efferent projections.
基于电生理学依据，有人提出存在从薄束核和楔束核（背柱核，DCN）到小脑的投射，但在用神经解剖学技术进行研究时受到质疑。本研究使用辣根过氧化物酶（HRP）逆行转运法，提供了DCN - 小脑通路的解剖学证据。在成年猫中，将1至6微升30%的HRP注入前叶中间部（小叶IV - V）、旁正中小叶以及前叶（小叶IV - V）和后叶（小叶VII）的蚓部。在存活24至48小时后，所有动物用双醛混合物灌注，并对延髓进行连续40微米切片，以孵育HRP进行可视化观察。在所有情况下，已知投射到小脑注射皮质区域的延髓核中含有HRP阳性神经元，主要在注射同侧（如外侧楔核）或主要在注射对侧（如下橄榄复合体）。在旁正中小叶或中间部进行同侧注射后，楔束核中的HRP阳性神经元集中在其吻侧部分，此处以具有放射状树突的多极细胞为主。相反，楔束核尾侧部分的簇状区域未显示HRP阳性颗粒。在前蚓部注射的情况下，薄束核吻侧部分有一些标记细胞，但在该核的簇状区域没有。在后蚓部注射后，未发现DCN神经元有明显标记。为了比较参与DCN - 小脑通路的细胞分布与DCN中丘脑中继细胞的分布，在另一组猫的丘脑腹后外侧核中注射0.5至3微升30%的HRP。与丘脑注射相对的一侧，标记细胞集中在薄束核和楔束核的簇状区域，但在这些核的吻侧，它们分散在未标记的神经元之间。投射到小脑的细胞和投射到丘脑的细胞在DCN中的优先位置强调了这些核沿头尾轴存在异质性组织。此外，结果表明，基于细胞构筑学（库伊珀斯和图尔克，'64）和传入纤维（鲁斯蒂奥尼，'73，'74）区分的DCN区域，其传出投射也有所不同。
