Epilepsy-associated alterations in hippocampal excitability
Epilepsy-associated alterations in hippocampal excitability
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DOI：
10.1515/revneuro-2016-0059
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发表时间：
2017-04-01
影响因子：
4.1
通讯作者：
Mehranfard, Nasrin
中科院分区：
文献类型：
--
作者：
Navidhamidi, Mojdeh;Ghasemi, Maedeh;Mehranfard, Nasrin
海马体表现出广泛的与癫痫相关的异常，位于边缘癫痫发作开始的内侧颞叶。这些异常可能会影响膜的兴奋性，并导致神经元过度刺激。多个重叠的过程是指神经元中发展的神经稳态反应，这些反应共同作用，将神经元的放电率恢复到控制水平。然而，稳态机制不能恢复正常的神经元兴奋性，癫痫患者的海马体变得过度兴奋或过度兴奋。研究表明，甚至在开始反复的自发性癫痫发作之前，就已经有了高兴奋性，这表明尽管海马区的高兴奋性可能有助于癫痫的发生，但单凭它还不足以产生癫痫发作。这支持了海马区并不是边缘癫痫发作的唯一底物的概念，更广泛的超兴奋边缘结构可能有助于颞叶癫痫(TLE)的发作。然而，在海马体表现出低兴奋性表型的情况下，也会发生癫痫发作。由于TLE发作最常起源于海马区，因此可以假设，海马区的兴奋性低下和过度兴奋性都是不受欢迎的状态，会使癫痫发作的海马区网络变得不稳定，并在某些条件下可能触发癫痫发作。
The hippocampus exhibits a wide range of -epilepsy-related abnormalities and is situated in the mesial temporal lobe, where limbic seizures begin. These abnormalities could affect membrane excitability and lead to overstimulation of neurons. Multiple overlapping processes refer to neural homeostatic responses develop in neurons that work together to restore neuronal firing rates to control levels. Nevertheless, homeostatic mechanisms are unable to restore normal neuronal excitability, and the epileptic hippocampus becomes hyperexcitable or hypoexcitable. Studies show that there is hyperexcitability even before starting recurrent spontaneous seizures, suggesting although hippocampal hyperexcitability may contribute to epileptogenesis, it alone is insufficient to produce epileptic seizures. This supports the concept that the hippocampus is not the only substrate for limbic seizure onset, and a broader hyperexcitable limbic structure may contribute to temporal lobe epilepsy (TLE) seizures. Nevertheless, seizures also occur in conditions where the hippocampus shows a hypoexcitable phenotype. Since TLE seizures most often originate in the hippocampus, it could therefore be assumed that both hippocampal hypoexcitability and hyperexcitability are undesirable states that make the epileptic hippocampal network less stable and may, under certain conditions, trigger seizures.