Measuring functional connectivity during distinct stages of a cognitive task
Measuring functional connectivity during distinct stages of a cognitive task
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DOI：
10.1016/j.neuroimage.2004.06.035
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发表时间：
2004-10-01
期刊：
影响因子：
5.7
通讯作者：
D'Esposito, M
中科院分区：
文献类型：
--
作者：
Rissman, J;Gazzaley, A;D'Esposito, M
功能性大脑成像数据固有的多元性质为探索认知任务期间解剖上不同的大脑区域如何相互作用提供了独特的机会。我们引入了一种使用事件相关的功能磁共振成像（fMRI）数据来表征区域间相互作用的新方法。该方法相对于现有分析技术的主要优点是它能够在认知任务的不同阶段对大脑区域之间的功能连接进行建模。该方法是通过使用单独的协变量对一般线性模型 (GLM) 背景下每个单独试验的每个阶段引发的活动进行建模来实现的。生成的参数估计值（β 值）根据其派生阶段进行排序，形成一组特定于阶段的 beta 系列。其β系列在给定阶段期间相关的区域被推断为在该阶段期间在功能上相互作用。为了验证试验间 beta 值的相关波动意味着功能连接的假设，我们将该方法应用于事件相关的 fMRI 数据集，其中受试者执行了两个序列敲击任务。与之前的电生理学和功能磁共振成像一致性研究一致，我们发现需要更多双手协调的任务会导致两个半球运动区域之间更强的相关性。然后将该方法应用于事件相关的功能磁共振成像数据集，其中受试者执行延迟识别任务。在该任务的各个组成阶段生成了独特的功能连接图，说明了如何在认知任务的孤立阶段中获得神经网络的重要和新颖的观察结果。 (C) 2004 Elsevier Inc. 保留所有权利。
The inherently multivariate nature of functional brain imaging data affords the unique opportunity to explore how anatomically disparate brain areas interact during cognitive tasks. We introduce a new method for characterizing inter-regional interactions using event-related functional magnetic resonance imaging (fMRI) data. This method's principle advantage over existing analytical techniques is its ability to model the functional connectivity between brain regions during distinct stages of a cognitive task. The method is implemented by using separate covariates to model the activity evoked during each stage of each individual trial in the context of the general linear model (GLM). The resulting parameter estimates (beta values) are sorted according to the stage from which they were derived to form a set of stage-specific beta series. Regions whose beta series are correlated during a given stage are inferred to be functionally interacting during that stage. To validate the assumption that correlated fluctuations in trial-to-trial beta values imply functional connectivity, we applied the method to an event-related fMRI data set in which subjects performed two sequence-tapping tasks. In concordance with previous electrophysiological and fMRI coherence studies, we found that the task requiring greater bimanual coordination induced stronger correlations between motor regions of the two hemispheres. The method was then applied to an event-related fMRI data set in which subjects performed a delayed recognition task. Distinct functional connectivity maps were generated during the component stages of this task, illustrating how important and novel observations of neural networks within the isolated stages of a cognitive task can be obtained. (C) 2004 Elsevier Inc. All rights reserved.