Broadband criticality of human brain network synchronization.
Broadband criticality of human brain network synchronization.
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DOI：
10.1371/journal.pcbi.1000314
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发表时间：
2009-03
影响因子：
4.3
通讯作者：
Bullmore E
中科院分区：
文献类型：
--
作者：
Kitzbichler MG;Smith ML;Christensen SR;Bullmore E
自组织临界性是人类大脑动力学的一个有吸引力的模型，但在神经成像测量的大规模系统中，它的存在几乎没有直接证据。一般来说，关键系统与分形或幂律缩放、空间和时间上的长期相关性以及响应外部输入的快速重构有关。在这里，我们考虑了相位同步的两种测量方法：锁相间隔，或一对（神经生理）过程之间耦合的持续时间，以及（脑功能）网络的全局同步的不稳定性。通过对Ising模型和Kuramoto模型这两个机械上截然不同的系统进行计算模拟，我们发现当这些系统处于临界状态时，这两个同步度量都具有幂律概率分布。然后，我们展示了从正常志愿者在休息条件下记录的功能MRI和脑磁图数据中成对和全局同步指标的幂律缩放。这些结果强烈表明，人类大脑功能系统存在于一种内源性的动态临界状态，其特征是长时间锁相和在全局同步状态下发生大的快速变化的概率大于随机，类似于之前在细胞系统中描述的神经元“雪崩”。此外，在频率区间为0.05-0.11 Hz至62.5-125 Hz的神经生理系统中，临界动力学的证据得到了一致的确认，这证实了临界性是人脑功能网络组织在大脑生理带宽的所有频率区间的特性。处于临界状态的系统处于有序行为和随机行为之间过渡的尖端。在这一点上，它们展示了在所有空间和时间尺度上的复杂波动模式。临界是一个有吸引力的大脑动力学模型，因为它优化了计算模型中的信息传递、存储容量和对外部刺激的敏感性。然而，迄今为止，几乎没有直接的实验证据证明人类大脑网络的关键动力学。在这里，我们考虑了动态系统组件之间功能耦合或相位同步的两个度量：系统中特定时间序列或过程对之间同步的锁相间隔或持续时间以及所有过程对之间全局同步的不稳定性。我们证实，这两个同步指标在两个临界动力学计算模型中以及在低频（<0.5 Hz，使用功能性MRI测量）和高频（1-125 Hz，使用脑磁图测量）下振荡的人脑功能系统中都表现出尺度不变的行为。我们得出的结论是，人类大脑功能网络在所有频率区间都表现出临界动态，我们将这种现象描述为宽带临界。
Self-organized criticality is an attractive model for human brain dynamics, but there has been little direct evidence for its existence in large-scale systems measured by neuroimaging. In general, critical systems are associated with fractal or power law scaling, long-range correlations in space and time, and rapid reconfiguration in response to external inputs. Here, we consider two measures of phase synchronization: the phase-lock interval, or duration of coupling between a pair of (neurophysiological) processes, and the lability of global synchronization of a (brain functional) network. Using computational simulations of two mechanistically distinct systems displaying complex dynamics, the Ising model and the Kuramoto model, we show that both synchronization metrics have power law probability distributions specifically when these systems are in a critical state. We then demonstrate power law scaling of both pairwise and global synchronization metrics in functional MRI and magnetoencephalographic data recorded from normal volunteers under resting conditions. These results strongly suggest that human brain functional systems exist in an endogenous state of dynamical criticality, characterized by a greater than random probability of both prolonged periods of phase-locking and occurrence of large rapid changes in the state of global synchronization, analogous to the neuronal “avalanches” previously described in cellular systems. Moreover, evidence for critical dynamics was identified consistently in neurophysiological systems operating at frequency intervals ranging from 0.05–0.11 to 62.5–125 Hz, confirming that criticality is a property of human brain functional network organization at all frequency intervals in the brain's physiological bandwidth. Systems in a critical state are poised on the cusp of a transition between ordered and random behavior. At this point, they demonstrate complex patterning of fluctuations at all scales of space and time. Criticality is an attractive model for brain dynamics because it optimizes information transfer, storage capacity, and sensitivity to external stimuli in computational models. However, to date there has been little direct experimental evidence for critical dynamics of human brain networks. Here, we considered two measures of functional coupling or phase synchronization between components of a dynamic system: the phase lock interval or duration of synchronization between a specific pair of time series or processes in the system and the lability of global synchronization among all pairs of processes. We confirmed that both synchronization metrics demonstrated scale invariant behaviors in two computational models of critical dynamics as well as in human brain functional systems oscillating at low frequencies (<0.5 Hz, measured using functional MRI) and at higher frequencies (1–125 Hz, measured using magnetoencephalography). We conclude that human brain functional networks demonstrate critical dynamics in all frequency intervals, a phenomenon we have described as broadband criticality.
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影响因子：
5.3
作者：
Achard, S;Salvador, R;Bullmore, ET
通讯作者：
Bullmore, ET
影响因子：
4.3
作者：
Achard S;Bullmore E
通讯作者：
Bullmore E
DOI：
10.1098/rsta.2007.2092
发表时间：
2008-02-13
影响因子：
5
作者：
Beggs, John M.
通讯作者：
Beggs, John M.
DOI：
10.1016/0013-4694(94)00181-2
发表时间：
1994-11-01
期刊：
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
影响因子：
--
作者：
BULLMORE, ET;BRAMMER, MJ;BINNIE, CD
通讯作者：
BINNIE, CD
影响因子：
8.6
作者：
Kiyono, K;Struzik, ZR;Yamamoto, Y
通讯作者：
Yamamoto, Y