PHYSIOLOGY OF MACAQUE HORIZONTAL CELLS: THEIR ROLE IN SPATIAL AND COLOR VISION

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 这个项目的目标是确定外视网膜的细胞类型在光适应、颜色编码和感受野结构中所起的作用。在过去的一年里，该项目通过表征敏感性调节、感受野结构和锥体输入，重点研究了H1水平细胞作为关键神经元间的作用。首先，我们在理解H1水平细胞的空间感受野如何影响视网膜内神经元的周围方面取得了重大进展。灵长类H1水平细胞通过缝隙连接相互电连接，并通过锥体-H1突触的反馈进入锥体-双极-神经节细胞通路。我们已经确定了直接突触输入和耦合输入如何相互作用形成感受野，并使用药理学和神经模拟测量了这些成分的相对贡献。在中央凹，耦合减少，H1细胞的感受野大小缩小，形成一个仅由少数视锥细胞组成的环境。这些结果有力地表明，这一途径是中心凹“侏儒”红绿颜色对抗途径的关键组成部分。最后，作为正在进行的外层视网膜敏感性调节研究的一部分，我们通过测量L视锥细胞、M视锥细胞和S视锥细胞在光适应的明视范围内的信号脱敏方式，表征了H1和H2水平细胞如何对视网膜光适应做出贡献。根据这些结果，我们得出结论，H1细胞和光感受器之间的第一个视网膜突触是视网膜外部敏感性调节的主要部位。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal of this project is to determine the role that the cell types of the outer retina play in light adaptation, color-coding and receptive field structure. Over the last year the project has focused on the role of the H1 horizontal cella key interneuronby characterizing sensitivity regulation, receptive field structure and cone input. First, we have made significant progress in understanding how the spatial receptive field of the H1 horizontal cell contributes to the surrounds of inner retinal neurons. The primate H1 horizontal cells are coupled to each other electrically by gap junctions and access the cone-bipolar-ganglion cell pathway by feedback at the cone-H1 synapse. We have determined how direct synaptic input and coupled input interact to form a receptive field and have measured the relative contributions of these components using pharmacology and neural simulations. In the fovea, coupling is reduced and the receptive field size of H1 cells shrinks to create a surround derived from only a handful of cones. These results suggest strongly that this pathway is a critical component of the foveal 'midget' red-green color-opponent pathway. Finally, as part of an ongoing study of sensitivity regulation in the outer retina we have characterized how H1 and H2 horizontal cells contribute to retinal light adaptation by measuring the way in which signals from L, M and S cones are desensitized over the photopic range of light adaptation. From these results we have concluded that the first retinal synapse between H1 cells and photoreceptors is a major site for sensitivity regulation in outer retina.