Empirical validation of directed functional connectivity.
Empirical validation of directed functional connectivity.
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DOI：
10.1016/j.neuroimage.2016.11.037
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发表时间：
2017-02-01
期刊：
影响因子：
5.7
通讯作者：
Cole MW
中科院分区：
文献类型：
--
作者：
Mill RD;Bagic A;Bostan A;Schneider W;Cole MW
绘制人脑连接体的影响方向代表了理解其功能结构的下一个阶段。然而，大量的方法学不确定性阻碍了定向连接方法的应用，定向连接方法主要通过嵌入在模拟功能性MRI（fMRI）和磁/脑电图（MEG/EEG）数据集中的“地面实况”连接模式进行验证。这种模拟依赖于许多生成假设，因此我们使用了一种不同的策略，涉及经验数据，其中可以有信心地预测地面实况定向连接模式。具体来说，我们利用了既定的“感官再激活”的效果，在情节记忆中，感官信息的检索重新激活区域参与感知的感觉方式。受试者在单独的功能磁共振成像和脑磁图会话中执行配对关联任务，其中听觉和视觉感觉区域之间的定向连接的地面真实反转在整个任务条件下被实例化。通过不同的算法，包括格兰杰因果关系和贝叶斯网络（Ideal）方法，以及通过功能磁共振成像（“原始”和去卷积）和源建模的脑磁图，成功地恢复了这种定向连接逆转。这些结果扩展了有向连接的模拟研究，并提供了实际的指导方针，使用这种方法在澄清因果机制的神经处理。
Mapping directions of influence in the human brain connectome represents the next phase in understanding its functional architecture. However, a host of methodological uncertainties have impeded the application of directed connectivity methods, which have primarily been validated via “ground truth” connectivity patterns embedded in simulated functional MRI (fMRI) and magneto-/electro-encephalography (MEG/EEG) datasets. Such simulations rely on many generative assumptions, and we hence utilized a different strategy involving empirical data in which a ground truth directed connectivity pattern could be anticipated with confidence. Specifically, we exploited the established “sensory reactivation” effect in episodic memory, in which retrieval of sensory information reactivates regions involved in perceiving that sensory modality. Subjects performed a paired associate task in separate fMRI and MEG sessions, in which a ground truth reversal in directed connectivity between auditory and visual sensory regions was instantiated across task conditions. This directed connectivity reversal was successfully recovered across different algorithms, including Granger causality and Bayes network (IMAGES) approaches, and across fMRI (“raw” and deconvolved) and source-modeled MEG. These results extend simulation studies of directed connectivity, and offer practical guidelines for the use of such methods in clarifying causal mechanisms of neural processing.