Task-related functional connectivity dynamics in a block-designed visual experiment.
Task-related functional connectivity dynamics in a block-designed visual experiment.
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DOI：
10.3389/fnhum.2015.00543
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发表时间：
2015
影响因子：
2.9
通讯作者：
Zhang Z
中科院分区：
文献类型：
--
作者：
Di X;Fu Z;Chan SC;Hung YS;Biswal BB;Zhang Z
使用功能磁共振成像 (fMRI) 研究大脑连接的任务调节对于了解支持认知和情感过程的大脑功能至关重要。心理生理交互（PPI）和动态因果建模（DCM）等现有方法通常隐含地假设连接模式在具有相同刺激的块设计任务上是稳定的。然而，这一假设缺乏可靠的数据驱动分析方法对高时间分辨率功能磁共振成像数据的实证验证。本研究通过估计不同大脑区域的 BOLD 反应之间的时变相关系数 (TVCC)，在亚秒级采样率 (TR = 0.645 s) 的简单块设计视觉棋盘实验中对功能连接 (FC) 的动态变化进行了详细检查。我们在双侧枕中回（MOG）和双侧梭状回（FuG）的几个视觉区域观察到可靠的与任务相关的 FC 变化（即，任务开始后 FC 短暂减少，然后回到基线）。重要的是，只有较高视觉区域（MOG）和较低视觉区域（FuG）之间的FC表现出这种动态模式。结果表明，简单地假设任务块期间持续的 FC 可能不足以捕获与任务相关的不同 FC 变化。对任务中 FC 动力学的研究可以提高我们对条件变化和不同激活大脑区域之间协调的理解。
Studying task modulations of brain connectivity using functional magnetic resonance imaging (fMRI) is critical to understand brain functions that support cognitive and affective processes. Existing methods such as psychophysiological interaction (PPI) and dynamic causal modeling (DCM) usually implicitly assume that the connectivity patterns are stable over a block-designed task with identical stimuli. However, this assumption lacks empirical verification on high-temporal resolution fMRI data with reliable data-driven analysis methods. The present study performed a detailed examination of dynamic changes of functional connectivity (FC) in a simple block-designed visual checkerboard experiment with a sub-second sampling rate (TR = 0.645 s) by estimating time-varying correlation coefficient (TVCC) between BOLD responses of different brain regions. We observed reliable task-related FC changes (i.e., FCs were transiently decreased after task onset and went back to the baseline afterward) among several visual regions of the bilateral middle occipital gyrus (MOG) and the bilateral fusiform gyrus (FuG). Importantly, only the FCs between higher visual regions (MOG) and lower visual regions (FuG) exhibited such dynamic patterns. The results suggested that simply assuming a sustained FC during a task block may be insufficient to capture distinct task-related FC changes. The investigation of FC dynamics in tasks could improve our understanding of condition shifts and the coordination between different activated brain regions.