Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, INSERM UMRS 975 - CNRS UMR 7225, Hôpital de la Pitié-Salpêtrière Paris, France ; Université Pierre et Marie Curie Paris, France.
Front Comput Neurosci. 2013 Oct 18;7:140. doi: 10.3389/fncom.2013.00140. eCollection 2013.
Between seizures the brain of patients with epilepsy generates pathological patterns of synchronous activity, designated as interictal epileptiform discharges (ID). Using microelectrodes in the hippocampal formations of 8 patients with drug-resistant temporal lobe epilepsy, we studied ID by simultaneously analyzing action potentials from individual neurons and the local field potentials (LFPs) generated by the surrounding neuronal network. We found that ~30% of the units increased their firing rate during ID and 40% showed a decrease during the post-ID period. Surprisingly, 30% of units showed either an increase or decrease in firing rates several hundred of milliseconds before the ID. In 4 patients, this pre-ID neuronal firing was correlated with field high-frequency oscillations at 40-120 Hz. Finally, we observed that only a very small subset of cells showed significant coincident firing before or during ID. Taken together, we suggested that, in contrast to traditional views, ID are generated by a sparse neuronal network and followed a heterogeneous synchronization process initiated over several hundreds of milliseconds before the paroxysmal discharges.
癫痫患者在发作间期大脑会产生同步的病理性活动模式，被称为发作间期癫痫样放电（ID）。我们使用微电极对 8 名耐药性颞叶癫痫患者的海马结构进行研究，通过同时分析单个神经元的动作电位和周围神经网络产生的局部场电位（LFP）来研究 ID。我们发现，大约 30%的神经元在 ID 期间增加了放电率，而 40%的神经元在 ID 后阶段放电率降低。令人惊讶的是，有 30%的神经元在 ID 前几百毫秒就表现出放电率的增加或减少。在 4 名患者中，这种 ID 前的神经元放电与 40-120Hz 的场高频振荡相关。最后，我们观察到只有很小一部分细胞在 ID 之前或期间表现出显著的同步放电。综上所述，我们认为，与传统观点相反，ID 是由稀疏的神经元网络产生的，并在阵发性放电前几百毫秒就开始了异质同步化过程。
