Preictal Activity of Subicular, CA1, and Dentate Gyrus Principal Neurons in the Dorsal Hippocampus before Spontaneous Seizures in a Rat Model of Temporal Lobe Epilepsy
Preictal Activity of Subicular, CA1, and Dentate Gyrus Principal Neurons in the Dorsal Hippocampus before Spontaneous Seizures in a Rat Model of Temporal Lobe Epilepsy
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DOI：
10.1523/jneurosci.0584-14.2014
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发表时间：
2014-12-10
影响因子：
5.3
通讯作者：
Buckmaster, Paul S.
中科院分区：
文献类型：
--
作者：
Fujita, Satoshi;Toyoda, Izumi;Buckmaster, Paul S.
以往的研究表明，颞叶癫痫患者的自发性癫痫发作可能是由海马神经元的动作电位放电增加。发作前活动具有潜在的重要性，因为它可能为预测癫痫发作即将发生的时间和了解自发性癫痫发作是如何产生的提供新的机会。我们评估了癫痫匹罗卡品治疗大鼠自发性癫痫发作时，海马下托、CA 1、CA 3和背侧海马齿状回中单个假定兴奋性神经元的局部场电位和单位活动。在海马下托，CA 1，齿状回，但不CA 3，神经元的平均动作电位放电率显着增加，并逐步开始2-4分钟前，当地记录自发性癫痫发作。在海马下托、CA 1和齿状回中，41-57%的神经元表现出发作前活动增加，在多次发作中具有显著的一致性，但CA 3没有。下托和CA 1区神经元发作前放电的增加与发作前θ波活动有关，而齿状回神经元发作前放电与θ波无关。此外，部分CA 1和齿状回神经元的放电频率也明显降低。这些结果表明，不同的海马亚区表现出不同的程度和潜在的潜在机制的发作前活动。尽管许多癫痫发作可能在其他脑区开始，但在背侧海马中发现下托、CA 1和齿状核神经元的发作前活动稳健且显著一致，这表明存在一个更广泛的神经元网络，其活动在自发性癫痫发作开始前几分钟发生变化。
Previous studies suggest that spontaneous seizures in patients with temporal lobe epilepsy might be preceded by increased action potential firing of hippocampal neurons. Preictal activity is potentially important because it might provide new opportunities for predicting when a seizure is about to occur and insight into how spontaneous seizures are generated. We evaluated local field potentials and unit activity of single, putative excitatory neurons in the subiculum, CA1, CA3, and dentate gyrus of the dorsal hippocampus in epileptic pilocarpine-treated rats as they experienced spontaneous seizures. Average action potential firing rates of neurons in the subiculum, CA1, and dentate gyrus, but not CA3, increased significantly and progressively beginning 2-4 min before locally recorded spontaneous seizures. In the subiculum, CA1, and dentate gyrus, but not CA3, 41-57% of neurons displayed increased preictal activity with significant consistency across multiple seizures. Much of the increased preictal firing of neurons in the subiculum and CA1 correlated with preictal theta activity, whereas preictal firing of neurons in the dentate gyrus was independent of theta. In addition, some CA1 and dentate gyrus neurons displayed reduced firing rates preictally. These results reveal that different hippocampal subregions exhibit differences in the extent and potential underlying mechanisms of preictal activity. The finding of robust and significantly consistent preictal activity of subicular, CA1, and dentate neurons in the dorsal hippocampus, despite the likelihood that many seizures initiated in other brain regions, suggests the existence of a broader neuronal network whose activity changes minutes before spontaneous seizures initiate.