Enhanced synchrony in epileptiform activity? - Local versus distant phase synchronization in generalized seizures
Enhanced synchrony in epileptiform activity? - Local versus distant phase synchronization in generalized seizures
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DOI：
10.1523/jneurosci.1046-05.2005
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发表时间：
2005-08-31
影响因子：
5.3
通讯作者：
Velazquez, JLP
中科院分区：
文献类型：
--
作者：
Dominguez, LG;Wennberg, RA;Velazquez, JLP
同步是复杂系统的基本特征，也是自组织的基本机制。关于癫痫样活动的传统公认观点认为，覆盖大大脑区域的超同步是全身性癫痫发作的标志。然而，最近的一些报告描述了发作事件之前和期间同步的大幅波动，从而对广泛的同步概念提出了质疑。在这项研究中，我们使用来自全身性癫痫发作的癫痫患者和正常对照受试者的脑磁图记录来解决局部（邻近）和远处皮质区域的相位同步（锁相）的程度，并探索在发作间期和发作期活动期间同步发生的特定频率范围的持续时间动态。研究发现，根据癫痫综合征，同步模式有所不同，原发性全身性失神发作在所有研究频段（3-55Hz）中比继发性（症状性）全身性癫痫或额叶癫痫的全身性强直性运动性发作显示出更多的远程同步性。然而，与远距离同步相比，所有癫痫发作的特点都是局部同步性增强。同一患者的不同癫痫发作的特定皮质区域之间的同步性存在波动，但在大多数研究的癫痫发作中，无论症状学如何，同步动态都存在恒定模式，表明癫痫发作是通过招募邻近的神经元网络来进行的。总之，这些数据表明，全身性癫痫发作期间广泛的“超同步”活动的概念可能具有误导性，并且仅对非常特定的神经元群和情况有效。
Synchronization is a fundamental characteristic of complex systems and a basic mechanism of self-organization. A traditional, accepted perspective on epileptiform activity holds that hypersynchrony covering large brain regions is a hallmark of generalized seizures. However, a few recent reports have described substantial fluctuations in synchrony before and during ictal events, thus raising questions as to the widespread synchronization notion. In this study, we used magnetoencephalographic recordings from epileptic patients with generalized seizures and normal control subjects to address the extent of the phase synchronization ( phase locking) in local (neighboring) and distant cortical areas and to explore the ongoing temporal dynamics for particular ranges of frequencies at which synchrony occurs, during interictal and ictal activity. Synchronization patterns were found to differ somewhat depending on the epileptic syndrome, with primary generalized absence seizures displaying more long-range synchrony in all frequency bands studied (3-55 Hz) than generalized tonic motor seizures of secondary ( symptomatic) generalized epilepsy or frontal lobe epilepsy. However, all seizures were characterized by enhanced local synchrony compared with distant synchrony. There were fluctuations in the synchrony between specific cortical areas that varied from seizure to seizure in the same patient, but in most of the seizures studied, regardless of semiology, there was a constant pattern in the dynamics of synchronization, indicating that seizures proceed by a recruitment of neighboring neuronal networks. Together, these data indicate that the concept of widespread "hypersynchronous" activity during generalized seizures may be misleading and valid only for very specific neuronal ensembles and circumstances.