Whole-brain, time-locked activation with simple tasks revealed using massive averaging and model-free analysis
Whole-brain, time-locked activation with simple tasks revealed using massive averaging and model-free analysis
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DOI：
10.1073/pnas.1121049109
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发表时间：
2012-04-03
影响因子：
11.1
通讯作者：
Bandettini, Peter A.
中科院分区：
文献类型：
--
作者：
Gonzalez-Castillo, Javier;Saad, Ziad S.;Bandettini, Peter A.
大脑是身体最大的能量消耗者，即使没有高要求的任务。电生理学家报告说，在刺激或任务期间，在与扰动有主要关系的区域之外，神经元正在放电。虽然意识的生物起源仍然难以捉摸，但有人认为它来自复杂的，连续的全脑神经元合作。尽管越来越多的证据表明，整个大脑都在不断地工作，并适应预测和驱动响应环境，在过去的20年中，基于任务的功能性MRI（fMRI）强调了大脑功能的定位主义观点，fMRI显示只有少数激活区域响应任务/刺激。在这里，我们挑战的证据表明，在最佳的噪音条件下，功能磁共振成像激活远远超出了与任务的主要关系的领域;和血氧水平相关的信号变化与任务时间出现在超过95%的大脑一个简单的视觉刺激加注意力控制任务。此外，我们表明，响应形状在不同区域之间存在很大差异，并且基于这些差异的全脑包裹产生在解剖学和功能上有意义的分布式集群，在半球之间对称，并且在受试者之间可重复。这些发现突出了功能性磁共振成像信号中的精致细节，超出了通常检查的范围，并强调了假阴性的普遍性，以及功能性磁共振成像图的稀疏性如何不是局部脑功能的结果，而是高噪音和过于严格的预测反应模型的结果。
The brain is the body's largest energy consumer, even in the absence of demanding tasks. Electrophysiologists report on-going neuronal firing during stimulation or task in regions beyond those of primary relationship to the perturbation. Although the biological origin of consciousness remains elusive, it is argued that it emerges from complex, continuous whole-brain neuronal collaboration. Despite converging evidence suggesting the whole brain is continuously working and adapting to anticipate and actuate in response to the environment, over the last 20 y, task-based functional MRI (fMRI) have emphasized a localizationist view of brain function, with fMRI showing only a handful of activated regions in response to task/stimulation. Here, we challenge that view with evidence that under optimal noise conditions, fMRI activations extend well beyond areas of primary relationship to the task; and blood-oxygen level-dependent signal changes correlated with task-timing appear in over 95% of the brain for a simple visual stimulation plus attention control task. Moreover, we show that response shape varies substantially across regions, and that whole-brain parcellations based on those differences produce distributed clusters that are anatomically and functionally meaningful, symmetrical across hemispheres, and reproducible across subjects. These findings highlight the exquisite detail lying in fMRI signals beyond what is normally examined, and emphasize both the pervasiveness of false negatives, and how the sparseness of fMRI maps is not a result of localized brain function, but a consequence of high noise and overly strict predictive response models.