Dynamic networks have been increasingly used to characterize brain connectivity that varies during resting and task states. In such characterizations, a connectivity network is typically measured at each time point for a subject over a common set of nodes representing brain regions, together with rich subject-level information. A common approach to analyzing such data is an edge-based method that models the connectivity between each pair of nodes separately. However, such approach may have limited performance when the noise level is high and the number of subjects is limited, as it does not take advantage of the inherent network structure. To better understand if and how the subject-level covariates affect the dynamic brain connectivity, we introduce a semi-parametric dynamic network response regression that relates a dynamic brain connectivity network to a vector of subject-level covariates. A key advantage of our method is to exploit the structure of dynamic imaging coefficients in the form of high-order tensors. We develop an efficient estimation algorithm and evaluate the efficacy of our approach through simulation studies. Finally, we present our results on the analysis of a task-related study on social cognition in the Human Connectome Project, where we identify known sex-specific effects on brain connectivity that cannot be inferred using alternative methods.
翻译:动态网络已越来越多地用于表征静息状态和任务状态下变化的大脑连接。在这种表征中,对于代表大脑区域的一组公共节点,通常在每个时间点上测量主题的连接网络,连同丰富的主题级别信息。一个常见的分析方法是基于边缘的方法,分别对每对节点之间的连接进行建模。然而,当噪声水平较高且主题数量有限时,这种方法的性能可能有限,因为它没有利用固有的网络结构。为了更好地理解主题级别协变量如何影响动态脑连接,我们引入了一种半参数动态网络反应回归方法,将动态脑连接网络与主题级别协变量的向量联系起来。我们方法的关键优势是利用高阶张量形式的动态成像系数结构。我们开发了一种高效的估计算法,并通过模拟研究评估了我们方法的有效性。最后,我们展示了我们在人类连接组计划中社交认知任务研究的分析结果,在那里我们发现了已知的性别特异性对大脑连接的影响,这些影响无法使用其他方法推断。