Neural circuits for visual feature detection

在美国，有相当大比例的人因创伤而致残 损伤、中风或导致视觉缺陷的退行性疾病。因此，一个 对基于特征的视觉的基本回路、神经生物学和神经调节的理解 感知将加深我们对视觉处理机制的理解，并且应该 促进开发针对这些残疾的治疗方法。 一种形式的视觉注意以视觉场景的显著特征为目标 受试者检测将显著物体与杂乱物体区分开来的光学差异 视觉环境。这种情况发生的细胞-电路机制还不是很清楚。这 更新项目将利用最近的发现和重大的实验优势 探索果蝇基于特征所需的基本神经回路 视觉上的注意。苍蝇有一个数字上简单的神经系统，通过它高度先进 基因技术可以用来识别、操纵和重复记录细胞的活动 单个神经元，以及它们的上下游网络伙伴。苍蝇也 显示基于特征的强大视觉感知，即使在失败的刺激条件下也是如此 运动视觉的经典模型，其类似的过程已局限于皮质 人类和非人类灵长类动物的路径。圆周率假设苍蝇探测到并 利用集成了特定电路的特殊电路来区分视觉对象的高阶特征 视网膜上的一阶基本运动信号，通过以下作用进一步增强 抑制性神经递质。PI将对候选细胞进行双光子钙离子成像 PI发现对刺激做出反应的通路可以引发果蝇的稳健特征检测 在虚拟现实飞行模拟器中。配备了生理接受区，PI将使用 在一只行为苍蝇中，活的成像技术可以直接读写活动模式，光遗传学可以直接写活动模式 观察特征检测加工对视觉行为的输入输出功能。最后，圆周率 将研究生物胺如何调节特征检测神经元的功能特性 在切换行为上下文中启用视觉特征检测所需的可塑性 从静止不动到主动运动的转变。

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.