Crossland W J, Hu X J, Rafols J A
Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, Michigan 48201.
J Comp Neurol. 1994 Sep 1;347(1):47-63. doi: 10.1002/cne.903470105.
We have studied the morphology of silver-impregnated neurons (rapid Golgi technique) in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), a center involved in the control of vertical and torsional saccadic eye movements. This morphological study of riMLF neurons in the rhesus monkey was undertaken to further our understanding of the functional circuitry of the oculomotor system. Our study employed Nissl, Golgi, and computer-assisted methods. The cytoarchitectonic boundaries of the riMLF and its relationships to neighboring structures were determined in both Nissl and Golgi preparations. Five (I-V) distinct morphological types of riMLF neurons were distinguished in the Golgi impregnations on the basis of soma size, dendritic size, numbers of primary dendrites, number of dendritic branch points, as well as form, number, and distribution of dendritic appendages. Type I neurons impregnated most frequently and had the most extensive and highly branched dendritic tree. Type II neurons displayed thick dendrites with complex dendritic appendages, but the dendritic tree was much more compact than that of type I cells. Type III and type V cells had fusiform somas and relatively unbranched dendritic trees but differed greatly in size as well as dendritic morphology. The type IV cell was the smallest neuron and had many characteristics of the local interneurons found in other thalamic, subthalamic, hypothalamic and midbrain centers. The type V was the largest neuron, least frequently impregnated, and found only at rostral riMLF levels. Digitized reconstructions of each type of neuron were rotated by the computer, which revealed that the dendritic trees of types I, III, and V occupy a disk-like compartment in the riMLF neuropil. In contrast, the tree of types II and IV occupy a roughly spherical compartment. We suggest that three of the cell types are well suited for specific purposes: type II cells for receiving topographically organized inputs that contain spatial information, type I cells for short-lead burst neuron output to the motor neurons or other premotor centers, and type IV cells for inhibitory inputs to type I cells.
我们利用快速高尔基技术，研究了内侧纵束吻侧间质核（riMLF）中经银浸染的神经元的形态，该核是一个参与垂直和扭转性眼球扫视运动控制的中枢。对恒河猴riMLF神经元进行的这项形态学研究，旨在加深我们对动眼神经系统功能回路的理解。我们的研究采用了尼氏染色法、高尔基染色法和计算机辅助方法。在尼氏染色和高尔基染色标本中，确定了riMLF的细胞构筑边界及其与相邻结构的关系。在高尔基染色标本中，根据细胞体大小、树突大小、一级树突数量、树突分支点数量以及树突附属物的形态、数量和分布，区分出了五种（I - V）不同形态类型的riMLF神经元。I型神经元浸染频率最高，其树突树最为广泛且分支众多。II型神经元的树突粗壮，带有复杂的树突附属物，但其树突树比I型细胞的要紧凑得多。III型和V型细胞具有梭形细胞体和相对无分支的树突树，但在大小和树突形态上差异很大。IV型细胞是最小的神经元，具有许多在其他丘脑、丘脑底核、下丘脑和中脑中枢中发现的局部中间神经元的特征。V型是最大的神经元，浸染频率最低，仅在riMLF吻侧水平发现。计算机对每种类型神经元的数字化重建进行了旋转，结果显示I型、III型和V型神经元的树突树占据riMLF神经毡中的一个盘状区域。相比之下，II型和IV型神经元的树突树占据一个大致呈球形的区域。我们认为，其中三种细胞类型非常适合特定目的：II型细胞用于接收包含空间信息的拓扑组织输入，I型细胞用于向运动神经元或其他运动前中枢输出短潜伏期爆发神经元信号，IV型细胞用于向I型细胞提供抑制性输入。
