Nikundiwe A M, Bjaalie J G, Brodal P
Department of Anatomy, University of Oslo, Norway.
Eur J Neurosci. 1994 Feb 1;6(2):173-86. doi: 10.1111/j.1460-9568.1994.tb00259.x.
This study deals with the three-dimensional arrangement of populations of pontocerebellar cell bodies projecting to the parafloccular complex. The fluorescent tracers rhodamine B isothiocyanate, fluoro-gold and fast blue were injected in either adjacent or separated cerebellar folia. A set of coordinates (x, y, z) was assigned to each retrogradely labelled cell and the total distribution reconstructed and displayed on a graphics workstation. At a large scale, we found that the majority of the cells of each labelled population (all projecting to the same folium) were confined to a lamella-shaped tissue volume. Each lamella extended from medial to lateral, and accordingly followed the curving of the pontine grey around the corticospinal and corticobulbar fibre tracts. At a smaller scale, i.e. within each lamellar subspace, the neurons belonging to one labelled population were distributed in aggregates of various shapes. To enable further analysis of the shapes of the intralaminar aggregates, we developed a computer program for unfolding of the lamellae, based on cubic B-spline approximation. The flattened reconstructions were three-dimensional polygonal windows, circumscribing the large majority of the labelled cell swarm (usually 70-80% of the total number of labelled cells in one population). The present findings, taken together with previous data on a gradual, rather than disjunctive, shift of pontocerebellar neuronal position in relation to a gradual shift of target region (Bjaalie et al., Anat. Rec.,231, 510-523, 1991), suggest that the cerebropontocerebellar system may be organized according to a set of fairly simple topographic rules.
本研究探讨了投射至旁绒球复合体的脑桥小脑细胞群体的三维排列。将异硫氰酸罗丹明、荧光金和快蓝等荧光示踪剂注射到相邻或分开的小脑小叶中。为每个逆向标记的细胞分配一组坐标（x, y, z），并重建总的分布情况，显示在图形工作站上。从宏观尺度来看，我们发现每个标记群体（均投射至同一小叶）的大多数细胞局限于一个薄片形的组织体积内。每个薄片从内侧延伸至外侧，相应地沿着脑桥灰质围绕皮质脊髓束和皮质延髓束的弯曲走行。在较小尺度上，即在每个薄片子空间内，属于一个标记群体的神经元呈各种形状的聚集分布。为了能够进一步分析层内聚集物的形状，我们基于三次B样条逼近开发了一个用于展开薄片的计算机程序。展开后的重建图像是三维多边形窗口，包围了大多数标记的细胞群（通常占一个群体中标记细胞总数的70 - 80%）。本研究结果与先前关于脑桥小脑神经元位置相对于目标区域的逐渐而非间断性移位的数据（Bjaalie等人，《解剖学记录》，231, 510 - 523, 1991）相结合，表明大脑 - 脑桥 - 小脑系统可能是根据一组相当简单的拓扑规则组织起来的。
