Dissecting Neural Circuitry in the Mammalian Retina

描述（来自申请人的摘要）：本项目的目标是 进一步了解视觉信息是如何被处理的。 视网膜的回路视网膜回路分为两层： 外网状层（OPL）和内网状层（IPL）。虽然很多 虽然知道OPL的贡献，但IPL的贡献很难 查明。该项目的目的是确定 IPL中的特定神经元细胞群。这将使用 靶向细胞类消融技术。方法是从基因上 设计细胞类，使其选择性地标记为 光活化染料一旦被标记，细胞可以通过光消融被杀死。 该方法已在体内和体外对几种不同的细胞进行了测试 在小鼠视网膜中的类，并显示> 90%的有效性与<2 非特异性细胞死亡百分比。通过这种方法，我们可以检验关于 通过将特定细胞群从电路中切除来控制其活动， 检查对视网膜输出的影响。我们的研究分为两部分 零件.首先是表征视网膜的响应特性， 输出神经元，神经节细胞，在老鼠的视网膜上。将使用鼠标 作为我们的模型系统，因为消融细胞的方法需要基因， 转移，并且小鼠适合于遗传操作。响应 神经节细胞的特性将通过呈现分离的 视网膜与光模式产生在计算机监视器和记录 神经节细胞的棘波列车与多电极阵列。第二部分是 确定特定群体的中间神经元在塑造这些 神经节细胞反应特性。本项目重点研究两种中间神经元 群体，i）表达神经肽-Y的无长突细胞，其被提议 在塑造对光做出反应的神经节细胞的行为中发挥作用 偏移（OFF细胞），和ii）儿茶酚胺能网间细胞，其是 根据对低等脊椎动物的研究，提出了作用于水平细胞， 双极细胞，并通过它们的作用，塑造中心/周围 神经节细胞感受野的组织。这些假设将得到检验 这些细胞群的其他行为将通过消融它们来检查 并评估神经节细胞反应特性的变化。 这些人群的解剖学和神经化学特性也将被 以获得关于这些细胞如何介导其效应的信息。这些 研究将提供有关视网膜回路如何处理 信息和深入了解电路故障背后的机制。

DESCRIPTION (From the Applicant's Abstract): The goal of this project is to advance our understanding of how visual information is processed by the circuitry of the retina. Retinal circuitry is divided into two layers: the outer plexiform layer (OPL) and the inner plexiform layer (IPL). While much is known about the contribution of the OPL, that of the IPL has been difficult to ascertain. The aim of this project is to determine the contributions of specific neuronal cell populations in the IPL. This will be addressed using a technique for targeted cell class ablation. The method is to genetically engineer the cell class so that it will selectively label with a photoactivatable dye. Once labeled, the cells can be killed by photoablation. This method has been tested in vivo and in vitro on several different cell classes in the mouse retina and shown to be >90 percent effective with <2 percent non-specific cell death. With this method, we can test hypotheses about the actions of a specific cell population by ablating it from the circuitry and examining the effects on retinal output. Our research is divided into two parts. The first is to characterize the response properties of the retinal output neurons, the ganglion cells, in the mouse retina. The mouse will be used as our model system, because the method for ablating cells requires gene transfer, and the mouse is amenable to genetic manipulation. The response properties of the ganglion cells will be examined by presenting the isolated retina with light patterns generated on a computer monitor and recording ganglion cell spike trains with a multi-electrode array. The second part is to determine the roles of specific populations of interneurons in shaping these ganglion cell response properties. This project focuses on two interneuron populations, i) neuropeptide-Y-expressing amacrine cells, which are proposed to play a role in shaping the behavior of ganglion cells that respond to light offset (OFF cells), and ii) catecholaminergic interplexiform cells, which are proposed, based on studies in lower vertebrates, to act on horizontal cells and bipolar cells, and, through their action, to shape the center/surround organization of ganglion cell receptive fields. These hypotheses will be tested and other actions of these cell populations will be examined by ablating them from the retina and assessing changes in ganglion cell response properties. Anatomical and neurochemical properties of these populations will also be examined to gain information about how these cells mediate their effects. These studies will provide basic information about how retinal circuits process information and insight into mechanisms that underlie circuit malfunctions.