Mechanisms of interictal spike generation

癫痫有两种病理表型：癫痫发作和发作间歇性棘波。 癫痫发作是相对罕见的大脑活动或同步化的持续升高，通常会产生 癫痫患者的意识丧失。发作间期棘波更频繁(On 每分钟1个数量级)，简短(~200ms)，并且没有行为表型(患者通常没有 意识到发作间期的尖峰)。众所周知，癫痫网络通常会产生这两种类型 出院和越来越多的证据表明发作间期尖峰和 癫痫发作。这一建议旨在剖析发作间期棘波产生的基本机制，即 将为癫痫神经网络的动力学提供新的见解(并反过来为发展提供信息 新的疗法)。 拟议的项目将使用一种可通过实验获得的 准备，器官型切片培养(自发地形成发作间期棘波和癫痫 在培养的第一周)，以及专门设计的定制显微镜(“探测镜”) 以单细胞分辨率记录和操纵整个癫痫网络的活动。成象 整个癫痫网络保证了观察到的癫痫样活动不是由外部因素驱动的 输入。此外，探测仪内置在组织培养孵化器内，能够连续、 随着癫痫活动的出现和演变，长达一个月的成像。这些发现将在完整的动物身上得到验证 使用基于内窥镜的发作间期棘波的活体成像。 该项目的主要目标如下：1)确定早期激发细胞亚群 发作间歇期的棘波。2)光学刺激早期放电细胞，以表征他们的 激活足以引发尖峰。3)光学抑制早期激发细胞，以表征其程度 它们的激活是启动尖峰信号所必需的。4)长期重复实验1-3(多 周)记录，以表征早期放电细胞的稳定性，并将观察到的变化与 癫痫发作和癫痫负担。5)在清醒的小鼠身上重复实验1，使用内窥镜和 海马内注射海人酸致癫痫模型，以检验是否有相同数量的细胞参与 在体内产生发作间期尖峰。

Epilepsy is characterized by two pathological electrographic phenotypes: seizures and interictal spikes. Seizures are relatively rare sustained elevations in brain activity or synchronization that often produce a loss of consciousness in patients suffering from epilepsy. Interictal spikes are much more frequent (on the order of 1 per minute), brief (~200ms), and have no behavioral phenotype (patient is typically not aware of interictal spikes). It is well-established that epileptic networks commonly generate both types of discharge and mounting evidence suggests that there is a direct link between interictal spikes and seizure onset. This proposal aims to dissect the basic mechanisms of interictal spike generation, which will offer new insight into the dynamics of epileptic neural networks (and, in turn, inform development of novel therapeutics). The proposed project will investigate the origins of interictal spikes using an experimentally accessible preparation, the organotypic slice culture (which spontaneously develops interictal spikes and seizures during its first weeks in culture), and a custom microscope (the “Incuscope”) specially designed to record and manipulate activity with single-cell resolution, across the entire epileptic network. Imaging the entire epileptic network guarantees that epileptiform activity observed is not driven by external input. Furthermore, the Incuscope is built inside of a tissue culture incubator, enabling continuous, month-long imaging as epileptic activity emerges and evolves. Findings will be validated in intact animals using endomicroscopy-based in vivo imaging of interictal spikes. The primary goals of this project are as follows: 1) Identify subpopulations of early-firing cells during interictal spikes. 2) Optically stimulate early-firing cells to characterize the degree to which their activation is sufficient to initiate spikes. 3) Optically inhibit early-firing cells to characterize the degree to which their activation is necessary to initiate spikes. 4) Repeat experiments 1-3 in long-term (multi- week) recordings to characterize the stability of early-firing cells and correlate observed changes with seizure onset and seizure burden. 5) Repeat experiment 1 in awake mice, using endomicroscopy and the intrahippocampal kainate model of epilepsy, to test whether the same population of cells is involved in generating interictal spikes in vivo.