Dynamics of high-frequency synchronization during seizures
Dynamics of high-frequency synchronization during seizures
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DOI：
10.1152/jn.00761.2012
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发表时间：
2013-05-01
影响因子：
2.5
通讯作者：
Bazhenov, Maxim
中科院分区：
文献类型：
--
作者：
Krishnan, Giri P.;Filatov, Gregory;Bazhenov, Maxim
神经元放电的病理同步被认为是癫痫发作的固有特性。然而，目前尚不清楚高频多单元活动以及局部场电位（LFP）的同步性是否会增加。我们利用对整个小鼠海马体内多达 60 个位置的多电极阵列记录的宽带（高达 2,000 Hz）频谱分析，对癫痫样活动期间的同步进行时空分析。我们的研究揭示了癫痫样放电过程中由细胞外钾升高引发的 LFP 轮廓的显着结构，以及电流汇和电流源相对于解剖结构的特征分布。与基线活动相比，癫痫发作期间跨通道高频活动（500 - 2,000 Hz）的交叉相干性有所降低，而较低频率则表现出相反的趋势。此外，癫痫样活动期间交叉相干性的大小取决于距离：靠近癫痫病灶的电极显示交叉相干性增加，而距离较远的电极显示高频活动的交叉相干性降低。这些实验观察结果被重新创建并在计算模型中得到支持。我们的研究表明，不同的内在和突触过程可以介导低频、中频和高频的阵发性同步。
Pathological synchronization of neuronal firing is considered to be an inherent property of epileptic seizures. However, it remains unclear whether the synchrony increases for the high-frequency multiunit activity as well as for the local field potentials (LFPs). We present spatio-temporal analysis of synchronization during epileptiform activity using wide-band (up to 2,000 Hz) spectral analysis of multielectrode array recordings at up to 60 locations throughout the mouse hippocampus in vitro. Our study revealed a prominent structure of LFP profiles during epileptiform discharges, triggered by elevated extracellular potassium, with characteristic distribution of current sinks and sources with respect to anatomical structure. The cross-coherence of high-frequency activity (500 - 2,000 Hz) across channels was reduced during epileptic bursts compared with baseline activity and showed the opposite trend for lower frequencies. Furthermore, the magnitude of cross-coherence during epileptiform activity was dependent on distance: electrodes closer to the epileptic foci showed increased cross-coherence and electrodes further away showed reduced cross-coherence for high-frequency activity. These experimental observations were re-created and supported in a computational model. Our study suggests that different intrinsic and synaptic processes can mediate paroxysmal synchronization at low, medium, and high frequencies.