How default is the default mode of brain function? Further evidence from intrinsic BOLD signal fluctuations
How default is the default mode of brain function? Further evidence from intrinsic BOLD signal fluctuations
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DOI：
10.1016/j.neuropsychologia.2006.06.017
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发表时间：
2006-01-01
期刊：
影响因子：
2.6
通讯作者：
Fransson, Peter
中科院分区：
文献类型：
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作者：
Fransson, Peter
脑功能的默认模式假说和静息时自发的内在低频信号波动的存在近年来引起了神经科学界的关注。在这项研究中，我们提出了两个问题：第一，是否有可能通过将大脑资源引导到目标导向和需要注意力的任务中，来削弱自我参照的大脑功能默认模式中的内在活动？第二，持续的注意力要求的外显任务表现对大脑中两个内在活跃的网络有什么影响，这两个网络是任务负性的、默认模式的网络和与任务相关的、任务正性的网络？我们使用功能磁共振成像监测自发内在活动在休息和持续性能的连续两回工作记忆任务。我们比较了内在活动在休息和两个回任务的信号增加和减少中观察到的一个时代相关的版本的工作记忆任务。我们的研究结果表明，自发的内在活动在默认模式的网络是不是熄灭，而是衰减的工作记忆任务的性能。此外，我们表明，在任务积极的网络的内在活动进行重组，以响应工作记忆任务。这里呈现的结果补充了早期的工作，这些工作表明默认模式区域中任务诱导的信号失活受到认知负荷的调节，还表明默认模式区域中固有的、自发的信号波动会持续存在并重新组织以响应外部的变化。工作负荷。(c)2006爱思唯尔有限公司保留所有权利。
The default mode of brain function hypothesis and the presence of spontaneous intrinsic low-frequency signal fluctuations during rest have recently attracted attention in the neuroscience community. In this study we asked two questions: First, is it possible to attenuate intrinsic activity in the self-referential, default mode of brain function by directing the brains resources to a goal-oriented and attention-demanding task? Second, what effect does a sustained attention-demanding overt task performance have on the two intrinsically active networks in the brain, those being the task-negative, default-mode and the anticorrelated, task-positive network? We used functional magnetic resonance imaging to monitor spontaneous intrinsic activity during rest and sustained performance of a sequential two-back working memory task. We compared intrinsic activity during rest and the two-back task to the signal increases and decreases observed in an epoch-related version of the working memory task. Our results show that spontaneous intrinsic activity in the default-mode network is not extinguished but rather attenuated during performance of the working memory task. Moreover, we show that the intrinsic activity in the task-positive network is reorganized in response to the working memory task. The results presented here complements earlier work that have shown that task-induced signal deactivations in the default-mode regions is modulated by cognitive load to also show that intrinsic, spontaneous signal fluctuations in the default-mode regions persist and reorganize in response to changes in external work load. (c) 2006 Elsevier Ltd. All rights reserved.