Kim Jaehee, Jeong Woorim, Chung Chun Kee
Department of Statistics, Duksung Women's University, Seoul, South Korea.
College of Sungsim General Education, Youngsan University, Gyeongnam, South Korea.
Front Neurosci. 2021 May 4;15:565029. doi: 10.3389/fnins.2021.565029. eCollection 2021.
To study the dynamic nature of brain activity, functional magnetic resonance imaging (fMRI) data is useful including some temporal dependencies between the corresponding neural activity estimates. Recent studies have shown that the functional connectivity (FC) varies according to time and location which should be incorporated into the model. Modeling this dynamic FC (DFC) requires time-varying measures of spatial region of interest (ROI) sets. To know about the DFC, change-point detection in FC is of particular interest. In this paper, we propose a method of detecting a change-point based on the maximum of eigenvalues via random matrix theory (RMT). From covariance matrices for FC of all ROI's, the temporal change-point of FC is decided by an RMT approach. Simulation results show that our proposed method can detect meaningful FC change-points. We also illustrate the effectiveness of our FC detection approach by applying our method to epilepsy data where change-points detected are explained by the changes in memory capacity. Our study shows the possibility of RMT based approach in DFC change-point problem and in studying the complex dynamic pattern of functional brain interactions.
为了研究大脑活动的动态特性,功能磁共振成像(fMRI)数据很有用,包括相应神经活动估计之间的一些时间依赖性。最近的研究表明,功能连接性(FC)会根据时间和位置而变化,这应纳入模型中。对这种动态功能连接性(DFC)进行建模需要对感兴趣的空间区域(ROI)集进行时变测量。为了了解DFC,FC中的变化点检测尤为重要。在本文中,我们提出了一种基于随机矩阵理论(RMT)通过特征值最大值来检测变化点的方法。从所有ROI的FC协方差矩阵中,通过RMT方法确定FC的时间变化点。模拟结果表明,我们提出的方法可以检测到有意义的FC变化点。我们还通过将我们的方法应用于癫痫数据来说明我们的FC检测方法的有效性,在癫痫数据中检测到的变化点可以通过记忆容量的变化来解释。我们的研究表明了基于RMT的方法在DFC变化点问题以及研究功能性大脑相互作用的复杂动态模式方面的可能性。