Spatiotemopral dynamics of epiletiform propagations in surgical specimens taken from patients with intractable epilepsy

癫痫发作活动通常起源于大脑皮层的一个局部区域，并扩散到大脑的大片区域。这些扩散性异常放电的性质可能解释了癫痫患者的临床表型，尽管它们的传播方式和潜在的机制尚不清楚。在本研究中，我们对手术切除的各种症状性病变引起的部分性癫痫患者的大脑皮质切片进行了黄素蛋白荧光成像。致痫组织中的神经活动瞬间水平扩散到大脑皮层，而来自无癫痫病史的脑肿瘤患者的对照组织中的神经活动仅显示出局部反应。特征性地，癫痫样传播包括早期和晚期。当刺激强度逐渐改变时，早期阶段呈现全有或全无行为，而晚期则呈现出逐渐增加的反应。此外，这两个阶段通过不同的大脑皮层传播，这表明它们来自不同的神经回路。形态学检查发现神经元肥大，树突棘丢失，这是成像的结果。这些发现表明，早期的同步活动可能在人类皮质癫痫中传播异常放电起关键作用。

Seizure activities often originate from a localized region of the cerebral cortex and spread across large areas of the brain. The properties of these spreading abnormal discharges may account for clinical phenotypes in epilepsy patients, although the manner of their propagation and the underlying mechanisms are not well understood. In the present study we performed flavoprotein fluorescence imaging of cortical brain slices surgically resected from patients with partial epilepsy caused by various symptomatic lesions. Elicited neural activities in the epileptogenic tissue spread horizontally over the cortex momentarily, but those in control tissue taken from patients with brain tumors who had no history of epilepsy demonstrated only localized responses. Characteristically, the epileptiform propagation comprised early and late phases. When the stimulus intensity was changed gradually, the early phase showed an all-or-none behavior, whereas the late phase showed a gradual increase in the response. Moreover, the two phases were propagated through different cortical layers, suggesting that they are derived from distinct neural circuits. Morphological investigation revealed the presence of hypertrophic neurons and loss of dendritic spines, which imaging. These findings indicate that synchronized activities of the early phase may play a key role in spreading abnormal discharges in human cortical epilepsies.