Morphological correlates of principal components of current source density profile in the frog optic tectum

在蛙类中，我们应用主成分分析(PCA)来表征产生顶盖神经元活动的不同神经元群体产生的时空电流源密度(CSD)模式，结果表明前三个主成分(PC)可以解释CSD变异的84%。在这里，我们还应用主成分分析(PCA)从40个高尔基染色的顶盖神经元获得了21个形态参数。分析表明，80%的测量形态参数的方差是由前六个PC所解释的。根据每个PC与每个形态参数相关的分量载荷，提出了每个PC可能的形态相关性如下。PC1对应于大的顶盖神经元，树突呈放射状扩张，胞体较大。PC2对应于小的顶盖神经元，具有垂直伸展的短树突。PC3和PC4分别对应于顶盖神经元，其垂直树突向上扩展至顶盖表面，胞体位于第6层或更深层，其树突和胞体垂直扩展位于第8层。最后，PC5和PC6分别对应于顶盖神经元，树突细小，分支较深，分支图案对称，基底支较多。根据这些发现，我们得出结论，生理PC1、PC2和PC3分别对应于形态PC3、PC4和PC2。

In the frog Rana catesbeiana, we have applied principal component analysis (PCA) to characterize the spatiotemporal current source density (CSD) patterns generated by distinct neuronal populations producing the tectal neuronal activity and showed that 84 per cent of the variance of the CSD was accounted for by the first three principal components (PCs).Here, to demonstrate their morphological correlates, we also applied PCA to 21 morphological parameters obtained from 40 Golgi-stained tectal neurons. The analysis showed that 80 per cent of the variance of measured morphological parameters was accounted for by the first six PCs. Judging from the component loadings of each PCs concerning each morphological parameters, possible morphological correlates of each PCs are proposed as follows. PC1 corresponded to large tectal neurons with radially expanding dendrites and large cell bodies. PC2 corresponded to small tectal neurons with vertically expanding short dendrites. PC3 and PC4 corresponded to tectal neurons with vertical dendrites expanding up to the tectal surface and cell bodies in layer 6 or deeper, and those with vertically expanding dendrites and cell bodies in layer 8, respectively. Finally, PC5 and PC6 corresponded to tectal neurons with thin dendrites branching profoundly, and those with symmetrical branching pattern and many basal branches, respectively. Based on these findings, we concluded that physiological PC1, PC2 and PC3 corresponded to morphological PC3, PC4 and PC2, respectively.