Neural circuits for visual feature detection

在美国，很大一部分人患有创伤性残疾， 损伤、中风或退行性疾病导致视觉缺陷。所以一间 了解基本电路神经生物学和基于特征的视觉神经调节 感知将加深我们对视觉处理机制的理解，并且应该 促进这些残疾的治疗方法的发展。 视觉注意力的一种形式是针对视觉场景的显著特征， 其中受试者检测将显著对象与杂乱对象区分开的光学视差， 视觉环境这种情况如何发生的细胞回路机制还不清楚。这 更新项目将利用最近的发现和重大的实验优势， 果蝇Drosophila探索基本的神经回路所需的功能为基础的 视觉注意力。苍蝇有一个数字简单的神经系统， 遗传技术可用于识别、操纵和重复记录 单个神经元，以及它们的上游和下游网络伙伴。苍蝇也 显示强大的基于特征的视觉感知，即使在刺激条件下， 经典模型的运动视觉，其中类似的过程已被定位到皮层 在人类和非人类灵长类动物中的通路。PI假设苍蝇检测到并 用专门的电路来区分视觉对象的高阶特征， 一阶基本运动信号的视网膜，这是进一步加强的行动， 抑制性神经递质PI将对候选细胞进行双光子Ca2+成像 PI发现，响应刺激的途径可以引起苍蝇的强大特征检测 在虚拟现实飞行模拟器中。有了生理感受野，PI将使用 实时成像"读取“和光遗传学”写入"行为苍蝇的活动模式， 观察特征检测处理对视觉行为的输入输出函数。最后，PI 将研究生物胺如何调节特征检测神经元的功能特性 为了实现在切换行为上下文中视觉特征检测所需的可塑性， 从静止的静止到活跃的运动的转变。

A significant percentage of people in the US suffer from disabilities resulting from traumatic injury, stroke, or degenerative disease which cause deficits in visual perception. Therefore, an understanding of the basic circuit neurobiology and neuromodulation of feature-based visual perception will sharpen our understanding of the mechanism of visual processing, and should facilitate the development of treatments for these disabilities. One form of visual attention is targeted to salient features of the visual scene, during which a subject detects optical disparities that distinguish a salient object from the cluttered visual surroundings. The cell-circuit mechanism for how this occurs is not well understood. This renewal project will capitalize on recent discoveries and significant experimental advantages of the fruit fly Drosophila to explore the elementary neural circuitry required for feature-based visual attention. The fly has a numerically simple nervous system, with which highly advanced genetic techniques can be used to identify, manipulate, and repeatedly record the activity of individual neurons, as well as their upstream and downstream network partners. The fly also displays robust feature-based visual perception, even under stimulus conditions that defeat classical models of motion vision, for which similar processes have been localized to cortical pathways in humans and non-human primates. The PI hypothesizes that flies detect and discriminate the higher-order features of visual objects with specialized circuits that integrate first-order elementary motion signals retinotopically, which are further enhanced by the action of inhibitory neurotransmitters. The PI will perform two-photon Ca2+ imaging of candidate cellular pathways in response to stimuli the PI has discovered to elicit robust feature detection by flies within a virtual reality flight simulator. Armed with physiological receptive fields, the PI will use live imaging to ‘read’ and optogenetics to ‘write’ activity patterns in a behaving fly to directly observe input-output functions of feature detection processing on visual behavior. Finally, the PI will study how biogenic amines modulate the functional properties of feature detecting neurons to enable plasticity required for visual feature detection in switching behavioral contexts such as the transition from stationary quiescence to active locomotion.