Capturing the spatiotemporal dynamics of self-generated, task-initiated thoughts with EEG and fMRI
Capturing the spatiotemporal dynamics of self-generated, task-initiated thoughts with EEG and fMRI
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DOI：
10.1016/j.neuroimage.2019.03.029
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发表时间：
2019-07-01
期刊：
影响因子：
5.7
通讯作者：
Jorge, Joao
中科院分区：
文献类型：
--
作者：
Brechet, Lucie;Brunet, Denis;Jorge, Joao
自我生成认知的时间结构是形成有意义的意识流的关键属性。休息时，我们的思想在不同的精神状态中从一个思想漫游到另一个思想。尽管正在进行的心理过程的显着重要性，它是具有挑战性的捕捉和这些状态与特定的认知内容。在这项工作中，我们采用超高场功能性磁共振成像（fMRI）和高密度脑电图（EEG）来研究参与者的持续思维，这些参与者被要求在22秒的时间内检索自我相关的过去事件。这些任务发起的，参与者驱动的活动模式进行了比较，一个独特的条件下，参与者进行了一系列的心算操作，从而从自我相关的自我无关的想法。BOLD活动映射显示，与心算条件相比，记忆期间颞叶、顶叶和枕叶区域的活动选择性增强，表明它们在记忆检索期间将重新经历的过去事件整合到有意识表征中的作用。功能连接性分析表明，这些区域被组织在两个主要的子部分，以前与“场景重建”和“自我体验”子系统。EEG微观状态分析允许通过确定短暂稳定的头皮电位场的时间动态来研究这些参与者在毫秒范围内驱动的想法。这项分析揭示了选择性调制的发生和持续时间的特定微观状态的记忆和心算条件，分别。EEG源分析揭示了这些微状态的源和与fMRI确定的区域的类似的空间分布。这些发现意味着与特定心理活动相关的区域的BOLD活动变化与心理状态的时间动态之间存在功能联系，并且支持越来越多的证据表明，特定的功能磁共振成像网络可以被EEG捕获为重复发生的短暂的整合连贯神经元活动，持续时间仅为几秒钟。
The temporal structure of self-generated cognition is a key attribute to the formation of a meaningful stream of consciousness. When at rest, our mind wanders from thought to thought in distinct mental states. Despite the marked importance of ongoing mental processes, it is challenging to capture and relate these states to specific cognitive contents. In this work, we employed ultra-high field functional magnetic resonance imaging (fMRI) and high-density electroencephalography (EEG) to study the ongoing thoughts of participants instructed to retrieve self-relevant past episodes for periods of 22sec. These task-initiated, participant-driven activity patterns were compared to a distinct condition where participants performed serial mental arithmetic operations, thereby shifting from self-related to self-unrelated thoughts. BOLD activity mapping revealed selective enhanced activity in temporal, parietal and occipital areas during the memory compared to the mental arithmetic condition, evincing their role in integrating the re-experienced past events into conscious representations during memory retrieval. Functional connectivity analysis showed that these regions were organized in two major subparts, previously associated to "scene-reconstruction" and "self-experience" subsystems. EEG microstate analysis allowed studying these participant-driven thoughts in the millisecond range by determining the temporal dynamics of brief periods of stable scalp potential fields. This analysis revealed selective modulation of occurrence and duration of specific microstates in the memory and in the mental arithmetic condition, respectively. EEG source analysis revealed similar spatial distributions of the sources of these microstates and the regions identified with fMRI. These findings imply a functional link between BOLD activity changes in regions related to a certain mental activity and the temporal dynamics of mentation, and support growing evidence that specific fMRI networks can be captured with EEG as repeatedly occurring brief periods of integrated coherent neuronal activity, lasting only fractions of seconds.