Vatansever D, Manktelow A E, Sahakian B J, Menon D K, Stamatakis E A
Division of Anaesthesia and Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.
Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom.
Hum Brain Mapp. 2017 Jan;38(1):41-52. doi: 10.1002/hbm.23341. Epub 2016 Aug 4.
Initially identified during no-task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large-scale brain networks. Nevertheless, its contribution to whole-brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI-based n-back paradigm with parametric increases in difficulty. Using a voxel-wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n-back task load. Subsequent seed-based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large-scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n-back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41-52, 2017. © 2016 Wiley Periodicals, Inc.
最初是在无任务的基线条件下被识别出来的，现在有人提出，默认模式网络（DMN）在各种工作记忆范式中通过与其他大规模脑网络的灵活交互而被激活。然而，其在工作记忆负荷增加时对全脑连接动力学的贡献尚未得到明确评估。我们研究的目的是在基于功能磁共振成像（fMRI）的n-back范式中，随着难度参数增加，确定哪些DMN枢纽与工作记忆任务表现相关。使用一种体素级度量，称为内在连接对比度（ICC），我们发现双侧角回（核心DMN枢纽）在n-back任务负荷的三个水平上显示出全局连接性的最大变化。随后基于种子点的功能连接分析表明，角回DMN区域与其他大规模脑网络有强烈的交互作用，这表明其可能参与了信息的全局整合。我们在角回连接性与正确反应的反应时间之间发现的显著相关性，进一步支持了这一假设。我们研究的意义在于，DMN在n-back任务中积极参与，因此在与工作记忆相关的方面发挥着重要作用，其核心角回区域随着环境需求增加而对全脑连接性变化做出贡献。《人类大脑图谱》38:41 - 52，2017年。© 2016威利期刊公司。
