Dissecting Neural Circuitry in the Mammalian Retina

描述(摘自申请者摘要)：该项目的目标是 加深我们对视觉信息是如何由 视网膜的回路。视网膜回路分为两层： 外网层(OPL)和内网层(IPL)。虽然很多都是 知道OPL的贡献，IPL的贡献一直很难 确定。该项目的目的是确定以下项目的贡献 IPL中特定的神经细胞群。这将通过使用 靶向细胞级消融技术。这种方法是从基因上 设计单元格类，以便它可以有选择地使用 光活化染料。一旦标记，这些细胞就可以通过光消融来杀死。 这种方法已经在几个不同的细胞上进行了体内和体外测试 在小鼠视网膜中的类，并显示&gt；90%有效与&lt；2 非特异性细胞死亡百分比。使用这种方法，我们可以测试关于以下方面的假设 特定细胞群通过将其从电路中消融而产生的行为 检查对视网膜输出的影响。我们的研究分为两部分 零件。第一个是描述视网膜的反应特性 输出神经元，小鼠视网膜中的神经节细胞。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，小鼠就可以接受基因操作。他们的回应 神经节细胞的特性将通过呈现分离的 在计算机监视器上产生光图案并记录的视网膜 神经节细胞棘波通过多电极阵列进行训练。第二部分是 确定特定的中间神经元群体在形成这些过程中的作用 神经节细胞反应特性。这个项目关注的是两个中间神经元 群体，i)神经肽-Y表达的无长突细胞，它被认为是 在塑造对光有反应的神经节细胞的行为中起作用 错位(脱离细胞)，以及ii)儿茶酚胺能网状细胞，它们是 根据对低等脊椎动物的研究，建议作用于水平细胞和 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。这些假说将得到检验。 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。 这些种群的解剖和神经化学性质也将是 检查以获得关于这些细胞如何调节其影响的信息。这些 研究将提供有关视网膜回路如何处理的基本信息 对电路故障背后的机制的信息和洞察。

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.