Cannon R C, Wheal H V, Turner D A
Neuroscience Research Group, School of Biological Sciences, Southampton University, Southampton, SO16 7PX, United Kingdom.
J Comp Neurol. 1999 Nov 1;413(4):619-33.
Dendrites of reconstructed hippocampal neurons were analyzed for morphometric, topologic, and fractal parameters (n = 32 quantities) to investigate neuronal groupings and growth characteristics with a common set of assumptions. The structures studied included CA1 and CA3 pyramidal cells, interneurons, and granule cells from young animals (71 cells in total). Most of the cells showed no characteristic fractal dimension; rather, the scaling relation could be well represented by a two-parameter fit, of which one parameter showed a significant difference between cell classes. Other significant quantities that differentiated cell classes were related to the complexity of the dendritic tree (number of branch points and maximal terminal branch order) and the cell's electrical properties such as the mean attenuation between the soma and terminals. Principal components analysis produced combined measures of only slightly greater discriminative power than the best individual measures, indicating that the elementary quantities capture most of the structural variation between hippocampal cell groups. Another finding was that for all cells the mean segment length increased with dendritic branch order, which is consistent with decreasing branching probability as a function of the path distance from the soma. Analysis of another set of CA1 pyramidal neurons from aged animals (n = 15; 22-24 months) showed only a few significant differences than those from young animals (n = 11; a subset of n = 71) of which the most important was a straightening of the paths between terminals and the soma. The quantities analyzed in these reconstructed hippocampal neurons may reflect both intrinsic neuronal characteristics and extrinsic influences. Hippocampal cell groupings (i.e., pyramidal cells as opposed to dentate granule cells and interneurons) were significantly differentiated by most parameters. These differences and parameter values may be critical for understanding and generating synthetic neuronal populations for modelling studies.
对重建的海马神经元的树突进行形态测量、拓扑和分形参数分析（n = 32个量），以在一组共同假设下研究神经元分组和生长特征。所研究的结构包括来自幼小动物的CA1和CA3锥体细胞、中间神经元和颗粒细胞（总共71个细胞）。大多数细胞没有特征性的分形维数；相反，标度关系可以用双参数拟合很好地表示，其中一个参数在细胞类别之间显示出显著差异。区分细胞类别的其他重要量与树突树的复杂性（分支点数和最大终末分支阶数）以及细胞的电学特性有关，例如胞体和终末之间的平均衰减。主成分分析产生的综合测量的判别能力仅略高于最佳的单个测量，这表明基本量捕获了海马细胞群之间的大部分结构变化。另一个发现是，对于所有细胞，平均节段长度随树突分支阶数增加，这与作为离胞体路径距离函数的分支概率降低一致。对另一组来自老年动物（n = 15；22 - 24个月）的CA1锥体细胞的分析显示，与来自幼小动物（n = 11；n = 71的一个子集）相比，只有少数显著差异，其中最重要的是终末和胞体之间路径的变直。在这些重建的海马神经元中分析的量可能反映了内在的神经元特征和外在影响。海马细胞分组（即锥体细胞与齿状颗粒细胞和中间神经元相对）在大多数参数上有显著差异。这些差异和参数值对于理解和生成用于建模研究的合成神经元群体可能至关重要。
