Song Pan-Pan, Xiang Jing, Jiang Li, Chen Heng-Sheng, Liu Ben-Ke, Hu Yue
Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China; Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China; Chongqing Key Laboratory of Pediatrics, Chongqing, China; China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.
Department of Neurology, MEG Center, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA.
Front Neurol. 2016 Nov 28;7:204. doi: 10.3389/fneur.2016.00204. eCollection 2016.
To analyze spectral and spatial signatures of high frequency oscillations (HFOs), which include ripples and fast ripples (FRs, >200 Hz) by quantitatively assessing average and peak spectral power in a rat model of different stages of epileptogenesis.
The lithium-pilocarpine model of temporal lobe epilepsy was used. The acute phase of epilepsy was assessed by recording intracranial electroencephalography (EEG) activity for 1 day after status epilepticus (SE). The chronic phase of epilepsy, including spontaneous recurrent seizures (SRSs), was assessed by recording EEG activity for 28 days after SE. Average and peak spectral power of five frequency bands of EEG signals in CA1, CA3, and DG regions of the hippocampus were analyzed with wavelet and digital filter.
FRs occurred in the hippocampus in the animal model. Significant dynamic changes in the spectral power of FRS were identified in CA1 and CA3. The average spectral power of ripples increased at 20 min before SE ( < 0.05), peaked at 10 min before diazepam injection. It decreased at 10 min after diazepam ( < 0.05) and returned to baseline after 1 h. The average spectral power of FRs increased at 30 min before SE ( < 0.05) and peaked at 10 min before diazepam. It decreased at 10 min after diazepam ( < 0.05) and returned to baseline at 2 h after injection. The dynamic changes were similar between average and peak spectral power of FRs. Average and peak spectral power of both ripples and FRs in the chronic phase showed a gradual downward trend compared with normal rats 14 days after SE.
The spectral power of HFOs may be utilized to distinguish between normal and pathologic HFOs. Ictal average and peak spectral power of FRs were two parameters for predicting acute epileptic seizures, which could be used as a new quantitative biomarker and early warning marker of seizure. Changes in interictal HFOs power in the hippocampus at the chronic stage may be not related to seizure occurrence.
通过定量评估癫痫发生不同阶段大鼠模型中的平均和峰值频谱功率，分析高频振荡（HFOs）的频谱和空间特征，高频振荡包括涟漪和快速涟漪（FRs，>200Hz）。
采用颞叶癫痫的锂-匹罗卡品模型。癫痫急性期通过在癫痫持续状态（SE）后记录1天的颅内脑电图（EEG）活动来评估。癫痫慢性期，包括自发反复癫痫发作（SRSs），通过在SE后记录28天的EEG活动来评估。使用小波和数字滤波器分析海马体CA1、CA3和DG区域EEG信号五个频段的平均和峰值频谱功率。
在动物模型的海马体中出现了快速涟漪。在CA1和CA3区域发现了快速涟漪频谱功率的显著动态变化。涟漪的平均频谱功率在SE前20分钟增加（<0.05），在注射地西泮前10分钟达到峰值。在注射地西泮后10分钟下降（<0.05），并在1小时后恢复到基线水平。快速涟漪的平均频谱功率在SE前30分钟增加（<0.05），在注射地西泮前10分钟达到峰值。在注射地西泮后10分钟下降（<0.05），并在注射后2小时恢复到基线水平。快速涟漪的平均和峰值频谱功率的动态变化相似。与SE后14天的正常大鼠相比，慢性期涟漪和快速涟漪的平均和峰值频谱功率均呈逐渐下降趋势。
高频振荡的频谱功率可用于区分正常和病理性高频振荡。快速涟漪的发作期平均和峰值频谱功率是预测急性癫痫发作的两个参数，可作为癫痫发作的新的定量生物标志物和早期预警指标。慢性期海马体发作间期高频振荡功率的变化可能与癫痫发作的发生无关。
