Ewell Laura A
Epilepsy Curr. 2019 Mar-Apr;19(2):117-118. doi: 10.1177/1535759719835350.
Altered Hippocampal Interneuron Activity Precedes Ictal Onset Miri ML, Vinck M, Pant R, Cardin JA. Elife. 2018;7. pii: e40750. doi:10.7554/eLife.40750. Although failure of GABAergic inhibition is a commonly hypothesized mechanism underlying seizure disorders, the series of events that precipitates a rapid shift from healthy to ictal activity remains unclear. Furthermore, the diversity of inhibitory interneuron populations poses a challenge for understanding local circuit interactions during seizure initiation. Using a combined optogenetic and electrophysiological approach, we examined the activity of identified mouse hippocampal interneuron classes during chemoconvulsant seizure induction in vivo. Surprisingly, synaptic inhibition from parvalbumin-(PV) and somatostatin-expressing (SST) interneurons remained intact throughout the preictal period and early ictal phase. However, these 2 sources of inhibition exhibited cell type-specific differences in their preictal firing patterns and sensitivity to input. Our findings suggest that the onset of ictal activity is not associated with loss of firing by these interneurons or a failure of synaptic inhibition but is instead linked with disruptions of the respective roles these interneurons play in the hippocampal circuit.
海马体中间神经元活动改变先于癫痫发作起始
米里·ML、温克·M、潘特·R、卡丁·JA。《eLife》。2018年；7。文章编号：e40750。doi:10.7554/eLife.40750。尽管γ-氨基丁酸能抑制功能失效是癫痫疾病常见的潜在发病机制，但导致从健康状态迅速转变为癫痫发作活动的一系列事件仍不清楚。此外，抑制性中间神经元群体的多样性对理解癫痫发作起始时的局部回路相互作用构成了挑战。我们采用光遗传学和电生理学相结合的方法，在体内化学惊厥诱导过程中研究了已鉴定的小鼠海马体中间神经元类别的活动。令人惊讶的是，在发作前期和癫痫发作早期，小白蛋白（PV）和生长抑素表达（SST）中间神经元的突触抑制作用始终保持完整。然而，这两种抑制来源在发作前期放电模式和对输入的敏感性方面表现出细胞类型特异性差异。我们的研究结果表明，癫痫发作活动的起始并非与这些中间神经元的放电丧失或突触抑制功能失效相关，而是与这些中间神经元在海马体回路中所起的各自作用受到破坏有关。
