Interneuron-based mechanisms of temporal lobe epilepsy

项目摘要/摘要 每26个美国人中就有一个在一生中患有癫痫。颞叶癫痫是最常见的癫痫之一 常见类型。三分之一的患者治疗失败。有效疗法的开发受到以下因素的限制 关于自发性癫痫是如何开始的，认识上存在差距。确定自发性癫痫是如何在 颞叶癫痫是我们的长期目标。被提议的项目的主要目标是检验假设 癫痫发作的开始，至少部分是因为抑制性中间神经元降低了它们的动作电位放电频率 (去激活)，这减少了对兴奋性神经元的抑制控制。第一个目标是测试中间神经元 失活是癫痫特有的。癫痫患者匹罗卡品多个脑区的局部场电位记录 治疗后的大鼠将被用来识别癫痫发作的起始部位。海马区同步单位记录 将对中间神经元进行评估，以测试中间神经元失活是否在 癫痫大鼠与对照组比较，癫痫发作部位与非发作部位比较。目标2是测试 防止神经元间失活可防止癫痫发作。多个脑区的局域场电位记录 将被用来识别腹侧海马区是癫痫发作焦点的大鼠。闭环式激活 中间神经元将防止癫痫发作部位的失活。光遗传学与Cre依赖 谷氨酸脱羧酶-Cre和小白蛋白-Cre转基因通道视紫红质表达病毒载体 大鼠将被用来选择性地激活特定的中间神经元亚型。光遗传刺激将是 由实时检测快速眼动睡眠触发，这在许多癫痫发作之前的大鼠模型中 颞叶癫痫。目的3是测试去激活中间神经元是否会导致癫痫发作。实验性的 方法将类似于目标2，除了新的氯离子传导光学蛋白SwiChR++将被用于 去激活中间神经元。我们的失活假说与其他人的观点相反，他们认为 中间神经元是癫痫发作的启动机制之一。拟议的项目将严格测试多个 关于颞叶细胞分裂的假说和对自发性癫痫如何开始的进一步理解。

Project Summary / Abstract Epilepsy affects 1 in 26 Americans over the course of a lifetime. Temporal lobe epilepsy is one of the most common types. Medical treatment fails in one-third of patients. Development of effective therapies is limited by gaps in knowledge about how spontaneous seizures begin. Determining how spontaneous seizures initiate in temporal lobe epilepsy is our long-term goal. The primary goal of the proposed project is to test the hypothesis that seizures start, at least in part, because inhibitory interneurons reduce their action potential firing frequency (deactivate), which reduces inhibitory control of excitatory neurons. Aim 1 is to test whether interneuron deactivation is seizure specific. Local field potential recordings from many brain regions in epileptic pilocarpine- treated rats would be used to identify sites of seizure initiation. Simultaneous unit recordings of hippocampal interneurons would be evaluated to test whether interneuron deactivation is more frequent and severe in epileptic versus control rats and at seizure onset sites versus non-onset sites. Aim 2 is to test whether preventing interneuron deactivation prevents seizures. Local field potential recordings from many brain regions would be used to identify rats in which the ventral hippocampus is the seizure focus. Closed-loop activation of interneurons would prevent deactivation at sites of seizure onset. Optogenetics and Cre-dependent channelrhodopsin-expressing viral vectors in glutamic acid decarboxylase-Cre and parvalbumin-Cre transgenic rats would be used to selectively activate specific interneuron subtypes. Optogenetic stimulation would be triggered by real-time detection of rapid eye movement sleep, which precedes many seizures in rat models of temporal lobe epilepsy. Aim 3 is to test whether deactivating interneurons causes seizures. The experimental approach would be similar to that of Aim 2, except the novel Cl--conducting opsin SwiChR++ would be used to deactivate interneurons. Our deactivation hypothesis is opposite of others that contend that hyperactivity of interneurons is a mechanism of seizure initiation. The proposed project would rigorously test multiple hypotheses of temporal lobe ictogenesis and advance understanding of how spontaneous seizures start.