School of Science, Beijing Jiaotong University, Beijing, China.
J Neurosci Methods. 2012 Jan 30;203(2):418-26. doi: 10.1016/j.jneumeth.2011.10.006. Epub 2011 Oct 15.
A lot of functional magnetic resonance imaging (fMRI) studies have indicated that Granger causality analysis (GCA) is a suitable method to reveal causal effect among brain regions. Based on another MATLAB GUI toolkit, Resting State fMRI Data Analysis Toolkit (REST), we implemented GCA on MATLAB as a graphical user interface (GUI) toolkit. This toolkit, namely REST-GCA, could output both the residual-based F and the signed-path coefficient. REST-GCA also intergrates a programme that could transform the distribution of residual-based F to approximately normal distribution and then permit parametric statistical inference at group level. Using REST-GCA, we tested the causal effect of the right frontal-insular cortex (rFIC) onto each voxel in the whole brain, and vice versa, each voxel in the whole brain on the rFIC, in a voxel-wise way in a resting-state fMRI dataset from 30 healthy college students. Using Jarque-Bera goodness-of-fit test and the Lilliefors goodness-of-fit test, we found that the transformation from F to F' and the further standardization from F' to Z score substantially improved the normality. The results of one sample t-tests on Z score showed bi-directional positive causal effect between rFIC and the dorsal anterior cingulate cortex (dACC). One sample t-tests on the signed-path coefficients showed positive causal effect from rFIC to dACC but negative from dACC to rFIC. All these results indicate that REST-GCA may be useful toolkit for caudal analysis of fMRI data.
许多功能磁共振成像（fMRI）研究表明，格兰杰因果分析（GCA）是揭示脑区之间因果关系的合适方法。基于另一个 MATLAB 图形用户界面（GUI）工具箱——静息态 fMRI 数据分析工具箱（REST），我们在 MATLAB 上实现了 GCA 作为一个图形用户界面（GUI）工具箱。这个工具箱，即 REST-GCA，可以输出基于残差的 F 和有符号路径系数。REST-GCA 还集成了一个程序，可以将基于残差的 F 的分布转换为近似正态分布，然后允许在组水平上进行参数统计推断。使用 REST-GCA，我们以体素为单位测试了右额岛盖皮层（rFIC）对全脑每个体素的因果效应，反之亦然，全脑每个体素对 rFIC 的因果效应，在 30 名健康大学生的静息态 fMRI 数据集上。使用 Jarque-Bera 拟合优度检验和 Lilliefors 拟合优度检验，我们发现 F 到 F'的转换以及 F'到 Z 分数的进一步标准化显著改善了正态性。Z 分数的单样本 t 检验结果显示 rFIC 与背侧前扣带皮层（dACC）之间存在双向正因果关系。rFIC 到 dACC 的有符号路径系数的单样本 t 检验显示出正因果关系，但 dACC 到 rFIC 的有符号路径系数则显示出负因果关系。所有这些结果表明，REST-GCA 可能是 fMRI 数据下游分析的有用工具包。
