OBJECTIVE Mesial temporal lobe epilepsy (MTLE) is one of the most common types of intractable epilepsy. The hippocampus and amygdala are two crucial structures of the mesial temporal lobe and play important roles in the epileptogenic network of MTLE. This study aimed to explore the effective connectivity among the hippocampus, amygdala, and temporal neocortex and to determine whether differences in effective connectivity exist between MTLE patients and non-MTLE patients. METHODS This study recruited 20 patients from a large cohort of drug-resistant epilepsy patients, of whom 14 were MTLE patients. Single-pulse electrical stimulation (SPES) was performed to acquire cortico-cortical evoked potentials (CCEPs). The root mean square (RMS) was used as the metric of the magnitude of CCEP to represent the effective connectivity. We then conducted paired and independent sample t-tests to assess the directionality of the effective connectivity. RESULTS In both MTLE patients and non-MTLE patients, the directional connectivity from the amygdala to the hippocampus was stronger than that from the hippocampus to the amygdala (P < 0.01); the outward connectivity from the amygdala to the cortex was stronger than the inward connectivity from the cortex to the amygdala (P < 0.01); the amygdala had stronger connectivity to the neocortex than the hippocampus (P < 0.01). In MTLE patients, the neocortex had stronger connectivity to the hippocampus than to the amygdala (P < 0.01). No significant differences in directional connectivity were noted between the two groups. CONCLUSIONS A unique effective connectivity pattern among the hippocampus, amygdala, and temporal neocortex was identified through CCEPs analysis. This study may aid in our understanding of physiological and pathological networks in the brain and inspire neurostimulation protocols for neurological and psychiatric disorders.

中文翻译：

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癫痫患者海马、杏仁核和颞叶新皮质之间的有效连接：皮质-皮质诱发电位研究

目的 颞叶内侧癫痫 (MTLE) 是最常见的顽固性癫痫类型之一。海马体和杏仁核是颞叶内侧的两个重要结构，在 MTLE 的致癫痫网络中起着重要作用。本研究旨在探索海马体、杏仁核和颞叶新皮质之间的有效连接，并确定 MTLE 患者和非 MTLE 患者之间是否存在有效连接的差异。方法 本研究从一大群耐药性癫痫患者中招募了 20 名患者，其中 14 名是 MTLE 患者。进行单脉冲电刺激 (SPES) 以获取皮质-皮质诱发电位 (CCEP)。均方根 (RMS) 用作 CCEP 大小的度量，以表示有效连通性。然后，我们进行了配对和独立样本 t 检验，以评估有效连接的方向性。结果无论是MTLE患者还是非MTLE患者，杏仁核到海马的定向连接都强于海马到杏仁核的定向连接（P < 0.01）；杏仁核到皮质的外向连通性强于皮层到杏仁核的内向连通性（P < 0.01）；与海马相比，杏仁核与新皮质的连接性更强（P < 0.01）。在 MTLE 患者中，新皮质与海马体的连接性比与杏仁核的连接性更强（P < 0.01）。两组之间在定向连接方面没有显着差异。结论 海马体、杏仁核、通过 CCEPs 分析确定了颞叶新皮层。这项研究可能有助于我们了解大脑中的生理和病理网络，并激发神经和精神疾病的神经刺激方案。