Zhou Xinlin, Li Mengyi, Zhou Hantao, Li Leinian, Cui Jiaxin
State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.
Beijing Advanced Innovation Center for Future Education, Beijing Normal University, Beijing, China.
Front Neurosci. 2018 Nov 6;12:817. doi: 10.3389/fnins.2018.00817. eCollection 2018.
Brain-behavior correlations are commonly used to explore the associations between the brain and human behavior in cognitive neuroscience studies. There are many critics of the correlation approach, however. Most problems associated with correlation approaches originate in the weak statistical power of traditional correlation procedures (i.e., the mean-wise interindividual brain-behavior correlation). This paper proposes a new correlation procedure, the item-wise interindividual brain-behavior correlation, which enhances statistical power via testing the significance of small correlation coefficients from trials against zero rather than simply pursuing the highest correlation coefficient. The item-wise and mean-wise correlation were compared in simulations and an fMRI experiment on mathematical problem-solving. Simulations show that the item-wise correlation relative to the mean-wise correlation results in higher values when signal-to-noise ratio is equal to or larger than 6%. Item-wise correlation displayed more voxels with significant brain-behavior correlation than did mean-wise correlation. Analyses with item-wise (rather than mean-wise) correlation showed significant brain-behavior correlation at the threshold of < 0.05 corrected. Cross validation showed that odd- and even-ordered trials have greater stability in terms of the item-wise correlation ( = 0.918) than the mean-wise correlation ( = 0.686). The simulations and example analyses altogether demonstrate the effectiveness of the proposed correlation procedure for task neuroimaging studies.
脑-行为相关性常用于认知神经科学研究中探索大脑与人类行为之间的关联。然而，相关性方法存在许多批评者。与相关性方法相关的大多数问题源于传统相关性程序（即个体间脑-行为平均相关性）的统计效力较弱。本文提出了一种新的相关性程序，即个体间逐项目脑-行为相关性，它通过检验来自试验的小相关系数与零的显著性来增强统计效力，而不是简单地追求最高相关系数。在模拟和一项关于数学问题解决的功能磁共振成像（fMRI）实验中对逐项目相关性和平均相关性进行了比较。模拟表明，当信噪比等于或大于6%时，相对于平均相关性，逐项目相关性会得出更高的值。逐项目相关性显示出比平均相关性更多具有显著脑-行为相关性的体素。使用逐项目（而非平均）相关性进行的分析在校正后<0.05的阈值下显示出显著的脑-行为相关性。交叉验证表明，就逐项目相关性（=0.918）而言，奇数和偶数顺序试验比平均相关性（=0.686）具有更高的稳定性。模拟和示例分析共同证明了所提出的相关性程序在任务神经成像研究中的有效性。
