Neural circuit mechanisms for color vision

项目总结(上级R01) 色彩视觉是我们感知世界的一个重要方面，它增强了我们对复杂物体的识别 视觉场景，并允许我们赋予它们一个身份和质量。颜色是如何在大脑中编码的？ 尽管进行了几十年的研究，这个问题仍然没有答案。人们普遍认为有色人种 在光谱的不同部分，神经元以相反的极性对波长做出反应，是建筑 用于色觉的块。然而，颜色对立的神经元信号是如何组合起来的，从而产生特定的色调 具有窄光谱敏感性的神经元，以及这些神经元如何对颜色感知做出贡献尚不清楚。 对遗传上易驯化的生物体中的颜色回路进行分析，对于回答这些问题至关重要。果蝇 黑素记录仪提供了一个强大的系统来研究紧凑的大脑是如何解决颜色编码问题的， 结合对特定细胞类型神经群体的遗传访问，明确定义的神经解剖学，以及 复杂的行为。此外，脊椎动物和无脊椎动物的视觉系统呈现出许多功能 相似之处。这些不同的系统在视觉处理问题的解决方案上表现出趋同的事实 在一个简单的模型中激发我们的调查，目的是提取相关的基本原则 到哺乳动物的系统。果蝇能够辨别颜色，并拥有必要的硬件 波长比较：四种锥形感光器，每种感光器都表达一个独特的窄带 视紫红质对波长的敏感度不同，从紫外线到绿色。然而，光谱信息的方式 这些光感受器是在大脑中被处理的，这是未知的，也是本提案的重点。我们将使用 遗传神经操纵技术、活体双光子成像、电生理学和行为分析 通过定量分析和建模，确定了计算算法和神经网络 控制色觉的机制。目标1将询问存在什么样的光谱对抗机制 并确定神经元的身份和潜在回路中的突触相互作用。我们会，在 此外，生成工具来干扰颜色对手的信号。AIM 2将使用Connectomics数据与 定义和功能表征彩色光感受器突触后颜色回路的示踪方法。我们 将研究颜色对立信号如何整合以产生更高阶的颜色神经元。目标3将 描述这些回路中神经元的反应如何支持先天的和后天的颜色引导 行为，标志着在颜色对抗、颜色回路和颜色之间建立因果联系的实验努力 知觉，这一方法在经典的、非基因可控的颜色视觉模型中一直是困难的。 这些研究将提供详细的了解，了解光谱信息是如何在苍蝇的大脑和 作为研究大脑中更复杂的颜色视觉的波长计算的指南 动物。

Project Summary (parent R01) Color vision is an important aspect of our perception of the world, enhancing our recognition of objects in complex visual scenes and allowing us to assign them an identity and quality. How are colors encoded in the brain? Despite decades of research, this question remains unanswered. It is widely accepted that color opponent neurons, responding with opposite polarity to wavelengths in different parts of the spectrum, are the building blocks for color vision. However, how color opponent neuron signals are combined to give rise to hue-specific neurons, with narrow spectral sensitivity, and how these neurons contribute to color perception is unknown. Analyses of color circuits in a genetically tractable organism are critical to answering these questions. Drosophila melanogaster provides a powerful system to investigate how a compact brain solves the problem of color coding, combining genetic access to cell-type-specific neural populations, a well-defined neural anatomy, and sophisticated behaviors. Moreover, vertebrate and invertebrate visual systems present many functional similarities. The fact that these diverse systems show convergence in solutions to visual processing problems motivates our investigation in a simple model, with the intention of extracting fundamental principles of relevance to mammalian systems. Fruit flies are capable color discrimination and have the hardware necessary for wavelength comparison: four types of cone-like photoreceptors each expressing a unique narrow-band rhodopsin of different wavelength sensitivity, ranging from UV to green. However, the way spectral information from these photoreceptors is processed in the brain is unknown and is the focus of this proposal. We will use genetic neural manipulation techniques, in vivo two-photon imaging, electrophysiology, and behavioral assays augmented by quantitative analysis and modeling, to identify the computational algorithms and neural mechanisms that govern color vision. Aim 1 will ask what kind of spectrally opponent mechanisms exist in Drosophila and determine the identity of neurons and synaptic interactions in the underlying circuits. We will, in addition, generate tools to disrupt color opponent signals. Aim 2 will use connectomics data in conjunction with tracing methods to define and functionally characterize color circuits postsynaptic to color photoreceptors. We will investigate how color-opponent signals are integrated to give rise to higher order color neurons. Aim 3 will characterize how the response of neurons in these circuits support both innate and learned color-guided behaviors, marking an experimental effort to draw a causal link between color opponency, color circuits and color perception, an approach that has been difficult in classical, non-genetically tractable, models for color vision. These studies will provide a detailed understanding of how spectral information is processed in the fly brain and serve as a guide to investigate wavelength computations underlying color vision in the brain of more complex animals.