Mechanisms of interictal spike generation

癫痫的特征在于两种病理性电图表型：癫痫发作和发作间期棘波。 癫痫发作是相对罕见的大脑活动或同步性的持续升高，通常会产生一种 癫痫患者的意识丧失。发作间期尖峰更频繁（在 每分钟1次）、短暂（~ 200 ms），并且没有行为表型（患者通常不是 意识到发作间期尖峰）。众所周知，癫痫网络通常会产生这两种类型 放电和越来越多的证据表明，有一个直接的联系之间的发作尖峰， 癫痫发作本研究的目的是探讨发作间期锋电位产生的基本机制， 将为癫痫神经网络的动力学提供新的见解（反过来， 新疗法）。 拟议的项目将使用一种实验上可获得的方法来研究发作间期尖峰的起源。 准备，器官型切片培养（自发发展发作间期尖峰和癫痫发作 在培养的第一周），和一个定制的显微镜（“Incuscope”），专门设计， 以单细胞分辨率记录和操纵整个癫痫网络的活动。成像 整个癫痫网络保证观察到的癫痫样活动不是由外部驱动的， 输入.此外，Incuscope内置于组织培养箱中， 一个月的成像作为癫痫活动的出现和发展。将在完整动物中验证结果 使用基于内窥镜的发作间期棘波的体内成像。 本研究的主要目的如下：1）鉴定早期放电细胞的亚群， 发作间期尖峰2)光学刺激早期放电细胞，以表征其 激活足以引发尖峰。3)光学抑制早期放电细胞的程度表征， 它们的激活是启动尖峰信号所必需的。4)在长期（多次）重复实验1-3。 记录以表征早期放电细胞的稳定性，并将观察到的变化与 癫痫发作和癫痫负荷。5)在清醒的小鼠中重复实验1，使用显微内镜和 海马内红藻氨酸盐癫痫模型，以测试是否相同的细胞群参与 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.