Estimation of the cortical functional connectivity with the multimodal integration of high-resolution EEG and fMRI data by directed transfer function
Estimation of the cortical functional connectivity with the multimodal integration of high-resolution EEG and fMRI data by directed transfer function
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DOI：
10.1016/j.neuroimage.2004.09.036
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发表时间：
2005-01-01
期刊：
影响因子：
5.7
通讯作者：
He, B
中科院分区：
文献类型：
--
作者：
Babiloni, F;Cincotti, F;He, B
如今，可以使用几种类型的脑成像装置来提供基于血液动力学，代谢或电磁测量的大脑皮质功能活性的图像。但是，在特定任务中激活的大脑区域的静态图像并不能传达这些区域如何相互通信的信息。在这项研究中，介绍了高分辨率脑电图（EEG）和功能磁共振成像（fMRI）数据估计皮质连通性的高级方法。这些方法包括由单个磁共振图像，多腹源模型和皮质电流密度的正则化线性逆源估计值构建的受试者的多室头模型（头皮，头骨，硬脑膜，皮层，皮层）。通过使用块设计的（活化体素的强度）fMRI揭示了从皮质区域的血液动力学区域中的信息中，对线性反问题的分辨率的测定进行了测定。我们通过计算模型的皮质地幔区域（ROI）的估计皮层电流密度波形上的有向的传递函数（DTF）来估计功能性皮质连通性。所提出的方法能够揭示感兴趣的皮质区域之间信息流的方向，因为它本质上是定向的。此外，此方法允许检测不同频带中皮质区域之间信息流的时间过程的变化。通过在四个健康受试者的视觉触发手指运动中收集的高分辨率脑电图和fMRI信号，进一步证明了这些技术的可靠性。针对此任务估算的连通性模式揭示了正确的顶壁和双侧前和额叶皮质区域的参与。这种皮质区域的参与类似于在先前的研究中揭示的，这些研究通过使用单独的EEG或fMRI测量值分析了视觉触发的手指运动。 （c）2004 Elsevier Inc.保留所有权利。
Nowadays, several types of brain imaging device are available to provide images of the functional activity of the cerebral cortex based on hemodynamic, metabolic, or electromagnetic measurements. However, static images of brain regions activated during particular tasks do not convey the information of how these regions communicate with each other. In this study, advanced methods for the estimation of cortical connectivity from combined high-resolution electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data are presented. These methods include a subject's multicompartment head model (scalp, skull, dura mater, cortex) constructed from individual magnetic resonance images, multidipole source model, and regularized linear inverse source estimates of cortical current density. Determination of the priors in the resolution of the linear inverse problem was performed with the use of information from the hemodynamic responses of the cortical areas as revealed by block-designed (strength of activated voxels) fMRI. We estimate functional cortical connectivity by computing the directed transfer function (DTF) on the estimated cortical current density waveforms in regions of interest (ROIs) on the modeled cortical mantle. The proposed method was able to unveil the direction of the information flow between the cortical regions of interest, as it is directional in nature. Furthermore, this method allows to detect changes in the time course of information flow between cortical regions in different frequency bands. The reliability of these techniques was further demonstrated by elaboration of high-resolution EEG and fMRI signals collected during visually triggered finger movements in four healthy subjects. Connectivity patterns estimated for this task reveal an involvement of right parietal and bilateral premotor and prefrontal cortical areas. This cortical region involvement resembles that revealed in previous studies where visually triggered finger movements were analyzed with the use of separate EEG or fMRI measurements. (C) 2004 Elsevier Inc. All rights reserved.