Sorokin Jordan M, Paz Jeanne T, Huguenard John R
Stanford Neurosciences Graduate Training Program, United States; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, United States.
Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, United States; Gladstone Institutes, San Francisco, CA 94158, United States.
J Physiol Paris. 2016 Nov;110(4 Pt A):372-381. doi: 10.1016/j.jphysparis.2017.05.004. Epub 2017 Jun 3.
Absence seizures are generalized, cortico-thalamo-cortical (CTC) high power electroencephalographic (EEG) or electrocorticographic (ECoG) events that initiate and terminate suddenly. ECoG recordings of absence seizures in animal models of genetic absence epilepsy show a sudden spike-wave-discharge (SWD) onset that rapidly emerges from normal ECoG activity. However, given that absence seizures occur most often during periods of drowsiness or quiet wakefulness, we wondered whether SWD onset correlates with pre-ictal changes in network activity. To address this, we analyzed ECoG recordings of both spontaneous and induced SWDs in rats with genetic absence epilepsy. We discovered that the duration and intensity of spontaneous SWDs positively correlate with pre-ictal 20-40Hz (β) spectral power and negatively correlate with 4-7Hz (Ø) power. In addition, the output of thalamocortical neurons decreases within the same pre-ictal window of time. In separate experiments we found that the propensity for SWD induction was correlated with pre-ictal β power. These results argue that CTC networks undergo a pre-seizure state transition, possibly due to a functional reorganization of cortical microcircuits, which leads to the generation of absence seizures.
失神发作是一种全身性的皮质 - 丘脑 - 皮质（CTC）高功率脑电图（EEG）或皮质电图（ECoG）事件，其起始和终止都很突然。在遗传性失神癫痫动物模型中，失神发作的ECoG记录显示出突然的棘波 - 慢波放电（SWD）起始，它从正常的ECoG活动中迅速出现。然而，鉴于失神发作最常发生在嗜睡或安静觉醒期间，我们想知道SWD起始是否与发作前网络活动的变化相关。为了解决这个问题，我们分析了遗传性失神癫痫大鼠自发和诱发SWD的ECoG记录。我们发现自发SWD的持续时间和强度与发作前20 - 40Hz（β）频谱功率呈正相关，与4 - 7Hz（Ø）功率呈负相关。此外，丘脑皮质神经元的输出在相同的发作前时间窗口内会减少。在单独的实验中，我们发现SWD诱发倾向与发作前β功率相关。这些结果表明，CTC网络经历了发作前的状态转变，这可能是由于皮质微电路的功能重组导致失神发作的产生。
