Arends J J, Zeigler H P
Biopsychology Program, Hunter College, City University of New York, New York 10021.
J Comp Neurol. 1991 Apr 8;306(2):221-44. doi: 10.1002/cne.903060203.
The projections of the cerebellar cortex upon the cerebellar nuclei and the vestibular complex of the pigeon have been delineated using WGA-HRP as an anterograde and retrograde tracer. Injections into individual cortical lobules (II-IXa) produce a pattern of ipsilateral terminal labeling of both the cerebellar and vestibular nuclei. The pattern of corticonuclear projections indicates both a rostrocaudal and a mediolateral organization with respect to the lobules and is consistent with a division of the cerebellar nuclei into a medial (CbM) and a lateral (CbL) nucleus. The retrograde experiments indicate that these nuclei receive projections, respectively, from Purkinje cells within medial (A) and lateral (C) longitudinal zones, which alternate with longitudinal zones (B, E) projecting upon the vestibular complex. Purkinje cells in (vestibulocerebellar) lobules IXb-X show only limited projections upon the cerebellar nuclei, but do project extensively upon the cerebellovestibular process (PCV), as well as upon the medial, superior, and descending vestibular nuclei. As the injection site shifts from medial to lateral, there is a corresponding shift in focus of the projection within PCV from areas bordering CbM to those abutting CbL. The topographic organization of corticovestibular projections is less clear-cut than those of the corticonuclear projections. Lobules II-X project upon the lateral vestibular nucleus (anterior lobe) or the dorsolateral vestibular nucleus (posterior lobe). These projections originate from either side of the lateral (C) zone. Projections originating from the medialmost (B) zone are interrupted in lobules VI and VII. The anterior and posterior portions of the lateralmost (E) zone overlap along lobules VI and VII. In addition, the E zone of the anterior lobe is the source of projections upon the medial, the descending, and the superior vestibular nuclei. Projections from the auricle and adjacent lateral unfoliated cortex (F zone) focus upon the infracerebellar nucleus, the medial tangential nucleus, and the medial division of the superior vestibular nucleus. The data suggest that the cerebellar cortex of the pigeon, like that of mammals, may be subdivided into a mediolaterally oriented series of longitudinal zones, with Purkinje cells in each zone projecting ipsilaterally to specific cerebellar nuclei or vestibular regions. For cortical regions exclusive of the auricle and lateral unfoliated cortex, three such zones (A, B, and C) are defined that are comparable in their efferent targets with the A, B, and C zones of mammals. There does not appear to be a D zone in the pigeon. The results are discussed in relation to comparative data on amphibians, reptiles, and mammals.
利用WGA-HRP作为顺行和逆行示踪剂，已描绘出鸽子小脑皮质向小脑核团和前庭复合体的投射。向各个皮质小叶（II-IXa）注射后，在小脑核团和前庭核团中均产生同侧终末标记的模式。皮质-核团投射模式显示，相对于小叶而言，存在前后向和内外侧组织，且与小脑核团分为内侧核（CbM）和外侧核（CbL）相一致。逆行实验表明，这些核团分别接受来自内侧（A）和外侧（C）纵向区内浦肯野细胞的投射，这两个纵向区与投射到前庭复合体的纵向区（B、E）交替出现。（前庭小脑）小叶IXb-X中的浦肯野细胞仅向小脑核团有有限的投射，但广泛投射到小脑-前庭突起（PCV）以及内侧、上和下行前庭核团。随着注射部位从内侧向外侧移动，PCV内投射的焦点相应地从小脑内侧核（CbM）边界区域转移到与小脑外侧核（CbL）相邻的区域。皮质-前庭投射的拓扑组织不如皮质-核团投射那样清晰。小叶II-X投射到外侧前庭核（前叶）或背外侧前庭核（后叶）。这些投射起源于外侧（C）区的两侧。起源于最内侧（B）区的投射在小叶VI和VII中中断。最外侧（E）区的前部和后部沿小叶VI和VII重叠。此外，前叶的E区是向内侧、下行和上前庭核团投射的来源。来自耳廓和相邻外侧无叶皮质（F区）的投射集中在下小脑核、内侧切向核和上前庭核的内侧部分。数据表明，鸽子的小脑皮质与哺乳动物的小脑皮质一样，可能可细分为一系列内外侧定向的纵向区，每个区内的浦肯野细胞同侧投射到特定的小脑核团或前庭区域。对于不包括耳廓和外侧无叶皮质的皮质区域，定义了三个这样的区（A、B和C），它们在传出靶标方面与哺乳动物的A、B和C区相当。鸽子中似乎不存在D区。结合关于两栖动物、爬行动物和哺乳动物的比较数据对结果进行了讨论。
