Amacrine Cell Circuitry Mediating Visual Function

描述(由申请人提供)：我们对视网膜活动的最深入了解来自于研究，这些研究表明已识别的无长突细胞类型如何调节特定的视觉功能。多轴突无长突细胞的扫视抑制和图形-背景分离，星形爆发式无长突细胞的定向选择性运动检测，以及所有无长突细胞对视杆视觉的处理，都是涉及特定类型的无长突细胞的明确视网膜回路介导的复杂功能的例子。这些研究的策略是确定无长突细胞产生的兴奋和抑制信号是如何整合在一起形成有意义的视网膜活动的。视网膜中还有20多个无长突细胞，它们的形态和分层已经很好地确定了，但它们的视觉功能仍然不清楚。这项建议的目的是研究许多这些定义较少的无长突细胞的视觉功能作用。我们的策略是利用我们最近对神经节细胞功能的研究，定义了十几个不同的“特征检测器”，这些“特征检测器”是由十几种不同类型的神经节细胞的树突整齐地分层形成的，分布在内丛状层的深处。这些研究定义了到达每种神经节细胞类型的树突的兴奋和抑制的空间、时间、分层和阶段特性。这些反应的抑制成分反映了不同类型的无长突细胞的空间、时间、层化和相态特性，其突起与每种神经节细胞类型的树突共层化。我们将从视网膜切片中记录特定的无长突细胞类型，并将它们的空间、时间、相位和分层特性与它们共同分层的神经节细胞的抑制特性相关联。通过这种关联过程，我们希望能够描述特定的无长突细胞在产生视觉功能的不同组成部分中所起的作用。

DESCRIPTION (provided by applicant): Our deepest understanding of retinal activity has been derived from studies that show how identified amacrine cell types mediate specific visual functions. Saccadic suppression and figure-ground separation by the polyaxonal amacrine cells, directional selective movement detection by the starburst amacrine cells, and the processing of rod vision by the All amacrine cells are examples of sophisticated function mediated by well-defined retinal circuitry involving specific amacrine cell types. The strategy in those studies was to determine how excitatory and inhibitory signals generated by amacrine cells are integrated to form meaningful retinal activity. There exist an additional two dozen amacrine cells in the retina whose morphology and stratification has been well defined, but whose visual functional roles still remain obscure. It is the goal of this proposal to investigate the visual functional role of many of these less defined amacrine cells. Our strategy is to utilize our recent studies of ganglion cell function that have defined a dozen different "feature detectors" formed by the neatly stratified dendrites of a dozen different ganglion cell types distributed throughout the depth of the inner plexiform layer. These studies define the space, time, stratification and phase properties of excitation and inhibition arriving at the dendrites of each ganglion cell type. The inhibitory components of these responses reflect the space, time, stratification and phase properties of different amacrine cell types whose processes costratify with the dendrites of each ganglion cell type. We will record from specific amacrine cell types in retinal slices and correlate their space time phase and stratification properties with the inhibitory properties of the ganglion cells with which they costratify. Through this correlation process we hope to be able to describe the role of specific amacrine cells in generating different components of visual function.