Scale-free properties of the functional magnetic resonance imaging signal during rest and task.
Scale-free properties of the functional magnetic resonance imaging signal during rest and task.
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DOI：
10.1523/jneurosci.2111-11.2011
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发表时间：
2011-09-28
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影响因子：
--
通讯作者：
He BJ
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文献类型：
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作者：
He BJ
最近的研究表明，脑电场电位的很大一部分由无标度动力学组成。这些无标度的大脑动力学包含复杂的时空结构，并通过任务性能进行调制。在这里，我们表明，从人类大脑记录的功能磁共振成像信号也是无标度的，其幂律指数区分大脑网络，并与功能磁共振成像信号方差和大脑葡萄糖代谢。重要的是，在平行于脑电场电位，方差和幂律指数的功能磁共振成像信号在任务激活过程中减少，这表明信号包含更多的远程记忆在休息期间，相反是更有效地在任务期间的在线信息处理。值得注意的是，类似的变化也发生在任务失活的大脑区域，揭示了功能磁共振成像信号的最佳动态范围的存在。fMRI信号和脑电场电位的无标度特性表明了它们各自的平稳性和非平稳性。这表明神经血管耦合机制可能包含一个从非平稳到平稳的转换过程。总之，我们的研究结果表明，功能磁共振成像信号的无标度特性的功能相关性，并施加约束，对未来的模型的神经血管耦合。
It has recently been shown that a significant portion of brain electrical field potentials consists of scale-free dynamics. These scale-free brain dynamics contain complex spatiotemporal structures and are modulated by task performance. Here we show that the fMRI signal recorded from the human brain is also scale-free; its power-law exponent differentiates between brain networks, and correlates with fMRI signal variance and brain glucose metabolism. Importantly, in parallel to brain electrical field potentials, the variance and power-law exponent of the fMRI signal decrease during task activation, suggesting that the signal contains more long-range memory during rest and conversely is more efficient at online information processing during task. Remarkably, similar changes also occurred in task-deactivated brain regions, revealing the presence of an optimal dynamic range in the fMRI signal. The scale-free properties of the fMRI signal and brain electrical field potentials bespeak their respective stationarity and nonstationarity. This suggests that neurovascular coupling mechanism is likely to contain a transformation from nonstationarity to stationarity. In summary, our results demonstrate the functional relevance of scale-free properties of the fMRI signal and impose constraints on future models of neurovascular coupling.