Genes and Visual Pigments of Red-Green Color Vision

描述(申请人提供)：我们的大部分日常活动都是在光线下进行的，我们的视觉是基于视锥感光细胞的。我们的长期目标是帮助理解视锥细胞视觉的基本机制，这些机制在视力障碍中是如何被破坏的，以及如何预防或扭转视力损失。对于这一应用，将使用心理物理学、自适应光学成像、电生理学和分子生物学的多学科方法来解决三个具体目标： 具体目标1.确定与X染色体锥体感光色素基因阵列相关的变异，这些变异与人类L和M锥体相对数量的变化有关。在色觉正常的人中，L：M视锥细胞比率存在惊人的个体差异。为了检验决定视锥细胞是M视锥还是L视锥的机制的假说，我们将在一大批色觉正常的男性样本中检测X染色体上含有视锥感光基因的区域，这些样本已知L和M视锥的比例存在差异。 具体目标2.确定已识别的影响光感受器地形图的遗传差异对人类视锥镶嵌的影响。自适应光学成像与视网膜密度测量相结合，将用于可视化视锥感光细胞的结构和功能变化及其在视网膜中的地形排列，这是基因突变的结果。 具体目标3.探索一种令人惊叹的可塑性神经机制，该机制被假设为允许来自环境的信息在一生中指导性地重组神经连接。我们将描述最近发现的成人视觉系统的可塑性，在这种系统中，改变的颜色经验被发现会改变成年人的颜色视觉的长期影响。这将使关于神经可塑性在建立和维持视觉系统正常功能方面的作用的假设得到检验。

DESCRIPTION (provided by applicant): Most of our daily activities are performed under light levels where our vision is based on cone photoreceptors. Our long term goal is to contribute to an understanding of the basic mechanisms underlying cone-based vision, how these mechanisms are disrupted in vision disorders and how vision loss might be prevented or reversed. For this application a multidisciplinary approach using psychophysics, adaptive optics imaging, electrophysiology, and molecular biology will be used to address three specific aims: Specific Aim 1. Identify variations linked to the X-chromosome cone photopigment gene array that are associated with shifts in the relative numbers of human L and M cones. There is astounding individual variation in the L:M cone ratio among humans with normal color vision. To test hypotheses about the mechanism responsible for determining whether a cone is M or L, the region of the X-chromosome containing the cone photopigment genes will be examined in a large sample of males with normal color vision who have known differences in the ratio of L:M cones. Specific Aim 2. Determine the consequences for the human cone mosaic of identified genetic differences that are proposed to affect the photoreceptor topography. Adaptive optics imaging coupled with retinal densitometry will be used to visualize structural and functional changes in the cone photoreceptors and their topographical arrangement in the retina as the result of genetic mutations. Specific Aim 3. Explore an amazing plastic neural mechanism that is hypothesized to allow information from the environment to instructively reorganize neural connections throughout life. We will characterize a recently discovered plasticity of the adult visual system in which the long term effects of altered chromatic experience have been found to change the color vision of adults. This will allow hypotheses about the role of neural plasticity in establishing and maintaining proper function of the visual system to be tested.