Mapping the optic lobes for color vision

绘制色觉视叶图

• 批准号: 7761663
• 负责人: Claude Desplan
• 金额: $ 33.71万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7761663
• 关键词: Address; Affect; Anatomy; Behavioral Genetics; Biological Neural Networks; Brain; Cells; Clone Cells; Color; Color Visions; Complement; Development; Discrimination; Drosophila genus; Electrophysiology (science); Event; Future; Genes; Image; Interneurons; Knowledge; Light; Logic; Maps; Mediating; Morphology; Neurons; Neurotransmitters; Optic Lobe; Output; Pattern; Photoreceptors; Play; Process; Reporter; Retina; Rhodopsin; Role; Signal Transduction; Structure; Time; Transgenic Organisms; UV sensitive; Visual system structure; Work; base; behavior test; cell type; color detection; color processing; gain of function; gene function; information processing; migration; molecular marker; nerve supply; neuroblast; neuromechanism; neuronal cell body; research study; tool; transcription factor

DESCRIPTION (provided by applicant): Color vision relies on the comparison in the brain of inputs from photoreceptors sensitive to different wavelengths of light. In the Drosophila retina, color detection is mediated within each ommatidium by different sets of photoreceptors that have different specializations and are distributed stochastically in the retina; p ommatidia appear to discriminate among short wavelengths while y ommatidia discriminate among longer wavelengths. The inner PR's project to the medulla part of the optic lobe where comparison between R7 and R8 (and perhaps between p and y PRs) occurs. We offer to investigate the color vision circuitry in the medulla: What types of neurons are contacted by R7 and R8; is there a difference between p and y target neurons? How do interneurons interconnect PRs and target neurons? The three specific aims will help us understand color vision processing in the Drosophila visual system. 1. Map medulla neurons. We have characterized the morphology and projection patterns of 15 types of medulla neurons involved in processing color vision. We will identify molecular markers for these neurons, establish their connectivity and the direction of information flow between them. We will investigate the type of neurotransmitters used by the PR target and by modulatory neurons. We will also attempt to uncover whether distinct maps independently process information from p and from y ommatidia, and whether a special map deals with comparison between p and y photoreceptors. 2. We will reconstruct the lineage of medulla cells and establish the logic of medulla development: Is it based on a columnar organization whereby one neuroblast gives rise to distinct neurons near each PR termination? Is there extensive migration of modulatory, non-columnar neurons? How many neuroblasts are required for the development of the medulla? 3. How does photoreceptor innervation or activity affect the establishment of the color vision network? We will genetically ablate or electrically silence each of the specific PR subtypes and study how medulla neurons are affected in their development and projection patterns, thus revealing possible inductive events from the retina to the optic lobes. To address the function of the genes that are specifically expressed in the various classes of medulla neurons, we will use loss- and gain of function experiments to define the role they play in cell fate determination. We hope to be able to build a precise anatomical description of the medulla that will complement classical work performed by Cajal and by Fischbach. In the future, this work will be followed by a functional analysis using behavior tests that we have developed, and through activity imaging and electrophysiology. This will provide precise information on the mechanisms by which Drosophila processes color information.

描述（由申请人提供）：色觉依赖于大脑中对不同波长的光敏感的感光器输入的比较。在果蝇视网膜中，颜色检测是由不同组的光感受器在每个小眼内介导的，这些光感受器具有不同的特化，并且随机分布在视网膜中。小眼似乎能区分短波长，而小眼则能区分较长波长。内部 PR 投射到视叶的髓质部分，在此处进行 R7 和 R8 之间（或许还有 p 和 y PR 之间）的比较。我们致力于研究髓质中的色觉回路：R7 和 R8 接触哪些类型的神经元； p 和 y 目标神经元之间有区别吗？中间神经元如何互连 PR 和目标神经元？这三个具体目标将帮助我们了解果蝇视觉系统中的颜色视觉处理。 1. 绘制髓质神经元图。我们对参与处理色觉的 15 种髓质神经元的形态和投射模式进行了表征。我们将识别这些神经元的分子标记，建立它们的连接性以及它们之间信息流的方向。我们将研究 PR 目标和调节神经元使用的神经递质类型。我们还将尝试揭示不同的图谱是否独立地处理来自 p 和 y 小眼的信息，以及是否有一个特殊的图谱处理 p 和 y 感光器之间的比较。 2. 我们将重建髓质细胞的谱系并建立髓质发育的逻辑：它是否基于柱状组织，其中一个神经母细胞在每个 PR 末端附近产生不同的神经元？调节性非柱状神经元是否存在广泛迁移？髓质的发育需要多少神经母细胞？ 3. 光感受器神经支配或活动如何影响色觉网络的建立？我们将对每种特定的 PR 亚型进行基因消融或电沉默，并研究髓质神经元的发育和投射模式如何受到影响，从而揭示从视网膜到视叶可能的感应事件。为了解决在各类髓质神经元中特异性表达的基因的功能，我们将使用功能丧失和获得实验来定义它们在细胞命运决定中发挥的作用。我们希望能够对髓质建立精确的解剖学描述，以补充卡哈尔和费施巴赫的经典工作。将来，这项工作将利用我们开发的行为测试以及活动成像和电生理学进行功能分析。这将提供有关果蝇处理颜色信息的机制的精确信息。