Dissecting Neural Circuit Computations in the Peripheral Visual System

项目摘要 R01 EY022638 解剖外周视觉系统中的神经回路计算 少年派：托马斯·R·克兰迪宁 视觉提供关键的感官输入，指导我们的日常行为；因此，失明 可能是我们所经历过的最具破坏性的剥夺。将感知与行动联系起来 在这种背景下，复杂的视觉场景必须有效地表征在神经活动中的相对较小 一组细胞；从这些信号中，特别是显著的线索被提取出来，与行为目标相结合，并且 链接到适当的回应。这些神经过程可以分解为以下几个单独的动作 相对简单的微电路，即执行广泛的基本操作的一小群神经元 在大脑中，但在不同的背景下，它们有不同的用途。这项提议发展了果蝇 视觉系统作为一个模型，其中这些微电路的功能可以在分子上进行解剖， 细胞和行为水平，并结合遗传学和系统神经科学的技术来 获得新的理解。 这项建议侧重于对视觉至关重要的三项计算。第一，一个基本电路 视觉系统中的过程将光信号的强度转换为对比度的估计， 相对于上一个强度的灯光级别。这种变换对应于取数学导数 一种输入操作，它在许多电路中执行，但它的电路和分子 实施情况未知。该提案的第一个目标是确定如何在 电路和分子水平。其次，检测运动的能力可能是最关键的视觉信号 由大脑提取，提供指导运动和导航的核心信息。新技术的出现 大脑中的这种方向选择性代表了长期存在的、具有丰富的 理论基础。然而，这些理论的电路和分子实现只是 不完全理解。这项提议的第二个目标是识别和剖析首先 提取运动信号。第三，视觉神经元对定向边缘的调节是代表 世界的空间结构。同样，允许神经元对这些功能进行调整的机制 只是不完全理解。该提案的第三个目标是确定结构和功能 定向选择电路的体系结构。 这些研究将广泛地帮助我们了解视网膜在健康和疾病中的功能。作为 直接刺激特定电路元件的视网膜假体的开发代表着一个重要的 治疗失明的可能性，了解这些回路如何编码与行为相关的视觉 信息代表着一个重要的目标。

Project Summary R01 EY022638 Dissecting neural circuit computations in the peripheral visual system PI: Thomas R. Clandinin Vision provides critical sensory inputs that guide our routine behaviors; as a result, blindness represents perhaps the most devastating deprivation we can experience. To connect perception to action in this context, complex visual scenes must be efficiently represented in the neural activities of relatively small groups of cells; from these signals, particularly salient cues are extracted, integrated with behavioral goals, and linked to the appropriate responses. These neural processes can be broken down into the individual actions of relatively simple microcircuits, small groups of neurons that perform elementary operations that are widespread in the brain, but which subserve distinct purposes in different contexts. This proposal develops the Drosophila visual system as a model in which the functions of these microcircuits can be dissected at the molecular, cellular and behavioral level, and combines techniques drawn from genetics and systems neuroscience to derive new understanding. This proposal focuses on three computations that are central to vision. First, one fundamental circuit process in the visual system transforms the intensity of a light signal into an estimate of contrast, the change in light level relative to a previous intensity. This transformation corresponds to taking the mathematical derivative of an input, an operation that is performed in many circuits, but one whose circuit and molecular implementation is unknown. The first goal of this proposal is to determine how this operation is implemented at the circuit and molecular level. Second, the ability to detect motion is probably the most critical visual signal extracted by the brain, providing information central to guiding movement and navigation. The emergence of this direction-selectivity in the brain represents a long-standing, paradigmatic neural computation with rich theoretical underpinnings. However, the circuit and molecular implementations of these theories are only incompletely understood. The second goal of this proposal is to identify and dissect the microcircuits that first extract motion signals. Third, the tuning of visual neurons for oriented edges is central to representing the spatial structure of the world. Again, the mechanisms that allow neurons to become tuned for these features are only incompletely understood. The third goal of this proposal is to determine the structure and functional architecture of orientation selective circuitry. These studies will broadly inform our understanding of retinal function in health and disease. As the development of retinal prostheses that directly stimulate specific circuit elements represents an important treatment possibility for blindness, understanding how these circuits can encode behaviorally-relevant visual information represents a important goal.