Neuronal avalanches in the resting MEG of the human brain.
Neuronal avalanches in the resting MEG of the human brain.
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DOI：
10.1523/jneurosci.4286-12.2013
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发表时间：
2013-04-17
期刊：
影响因子：
--
通讯作者：
Plenz D
中科院分区：
文献类型：
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作者：
Shriki O;Alstott J;Carver F;Holroyd T;Henson RN;Smith ML;Coppola R;Bullmore E;Plenz D
健康人类受试者正常皮质动力学的构成是什么是系统神经科学的一个主要问题。大量的体外和体内动物研究表明，持续或静息的皮质动力学的特征是跨多个空间尺度的级联活动，称为神经元雪崩。在实验和理论中，雪崩动力学通过两种措施来识别：（1）指数为−3/2的活动级联大小分布的幂律；（2）临界值为1的分支参数，反映活动在过早终止和潜在爆炸边界处的平衡传播。在这里，我们分析了使用无创脑磁图 (MEG) 记录的 124 名健康受试者和两个使用不同传感器技术的不同 MEG 设施记录的静息态大脑活动。我们识别出单个 MEG 传感器的大偏转，并使用多个时间尺度将它们组合成传感器阵列上的时空级联。级联大小分布遵循幂律。对于分支参数接近 1 的时间尺度，幂律指数为 -3/2。这种关系对于传感器阵列的缩放和粗粒度来说是稳健的。它在具有相同功率谱或空扫描仪数据的相改组控制中不存在。我们的结果表明，健康人类受试者在休息时的正常皮质活动会组织为神经元雪崩，并且可以通过关键的分支过程得到很好的描述。理论和实验表明，这种关键的、无标度的动态优化了信息处理。因此，我们的研究结果表明人脑获得了信息处理的最佳动态状态。
What constitutes normal cortical dynamics in healthy human subjects is a major question in systems neuroscience. Numerous in vitro and in vivo animal studies have shown that ongoing or resting cortical dynamics are characterized by cascades of activity across many spatial scales, termed neuronal avalanches. In experiment and theory, avalanche dynamics are identified by two measures: (1) a power law in the size distribution of activity cascades with an exponent of −3/2 and (2) a branching parameter of the critical value of 1, reflecting balanced propagation of activity at the border of premature termination and potential blowup. Here we analyzed resting-state brain activity recorded using noninvasive magnetoencephalography (MEG) from 124 healthy human subjects and two different MEG facilities using different sensor technologies. We identified large deflections at single MEG sensors and combined them into spatiotemporal cascades on the sensor array using multiple timescales. Cascade size distributions obeyed power laws. For the timescale at which the branching parameter was close to 1, the power law exponent was −3/2. This relationship was robust to scaling and coarse graining of the sensor array. It was absent in phase-shuffled controls with the same power spectrum or empty scanner data. Our results demonstrate that normal cortical activity in healthy human subjects at rest organizes as neuronal avalanches and is well described by a critical branching process. Theory and experiment have shown that such critical, scale-free dynamics optimize information processing. Therefore, our findings imply that the human brain attains an optimal dynamical regime for information processing.