Functional stratification of sensory encoding in a biological gyroscope

飞虫是地球上最具机动性的动物之一，它们必须快速整合来自多种感官的信息，以实现对运动的精细控制。例如，苍蝇将来自眼睛的输入和被称为笼头的哑铃形状的小结构结合起来，既能保持稳定，又能进行空中机动。笼头位于前翼后面，由后翼进化而来。笼头是众所周知的生物陀螺仪，检测身体旋转，进而触发一系列稳定反射，包括翅膀运动的变化。在它们的底部，有数百个生物应变计，被称为钟形感受器，为翅膀操纵肌肉提供每次振翅的直接反馈。最近的证据表明，在飞行过程中，前肢受到主动控制，使其成为一个多功能的感觉器官，帮助苍蝇在空中进行机动并保持平衡。然而，肢端如何完成这些双重角色，以及这些角色如何与翅膀肌肉的活动联系起来，仍然不清楚。更全面地了解haltere在飞行控制中的作用，将有助于深入了解这种独特的感觉器官是如何赋予苍蝇精致的飞行能力的。该项目涉及与莫尔黑德天文馆的合作，利用首席研究员在非正式教育方面的丰富经验，通过卡罗莱纳科学学院促进公众对话。此外，来自代表性不足群体的本科生将在整个项目中进行研究指导。最后，这项研究的结果将有助于开发微型飞行器在复杂环境中导航。这一建议的目的是揭示感觉编码和感觉运动处理的原则，苍蝇使用在控制半空，从而，他们的空中机动。这项研究将集中在果蝇身上，并将新的活体成像技术与计算神经科学和肌肉电生理学的分析方法结合起来。通过基因编码的光学钙传感器GCaMP的表达，可以直接观察到在视觉引导的飞行机动过程中haltere钟形感器的活动。这些实验将验证这样一种假设，即前额叶的特定区域编码视觉运动的不同方面，如方向或角速度。然后，反向相关分析将用于构建定量模型，以测试这些不同的区域是否在主动机动期间以线性或非线性的方式被招募。最后，同时钙成像和电生理学的翅膀转向肌肉将解决如果翅膀肌肉的功能划分是源自于halte的特定区域。此外，这项工作将证明机械传感器的安排和位置如何作为行为相关刺激的过滤器。通过采用一种有机的方法，并将感觉结构的微观力学与飞行行为联系起来，这些实验将清楚地表明导致haltere进化的选择压力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Flying insects are among the most maneuverable animals on the planet, and must rapidly integrate information from multiple senses to achieve fine-scale control of locomotion. For example, flies combine input from the eyes and small, dumbbell-shaped structures known as halteres to both maintain stability and perform aerial maneuvers. The halteres are located behind the forewings and evolved from the hindwings. The halteres are well-known as biological gyroscopes, detecting body rotations that in turn trigger a number of stabilization reflexes, including changes in wing motion. At their base, the halteres possess hundreds of biological strain gauges, known as campaniform sensilla, that provide the wing steering muscles with direct feedback each wingstroke. Recent evidence suggests that the haltere is under active control during flight, making it a multifunctional sensory organ that helps flies perform maneuvers and still maintain their balance while in the air. However, how the haltere accomplishes these dual roles, and how these roles relate to the activity of the wing muscles, remains unclear. A more complete understanding of the haltere’s role in flight control will provide insight into how this unique sensory organ endows flies with their exquisite flight capacities. This project involves a collaboration with the Morehead Planetarium that takes advantage of the principal investigator’s extensive experience in informal education to foster public dialogue through Carolina Science Cafés. Additionally, undergraduates from underrepresented groups will be mentored in conducting research throughout this project. Finally, the results from this research will help develop micro air vehicles navigate complex environments.The goal of this proposal is to reveal the principles of sensory encoding and sensorimotor processing that flies use in controlling the haltere, and thus, their aerial maneuvers. The research will focus on the fruit fly, Drosophila melanogaster, and combine new in vivo imaging techniques with analysis approaches drawn from computational neuroscience and muscle electrophysiology. Through expression of the genetically-encoded, optical calcium sensor GCaMP, the activity of haltere campaniform sensilla during visually-guided flight maneuvers will be directly observed. These experiments will test the hypothesis that specific regions of the haltere encode different aspects of visual motion, such as direction or angular velocity. Then, reverse correlation analysis will be used to construct quantitative models that test if these different regions are recruited in a linear or nonlinear fashion during active maneuvers. Finally, simultaneous calcium imaging and electrophysiology of the wing steering muscles will address if the functional divisions of the wing muscles are derived from particular regions of the haltere. Furthermore, this work will demonstrate how the arrangement and location of mechanosensors acts as a filter for behaviorally relevant stimuli. By taking an organismal approach, and linking the micromechanics of sensory structures with flight behavior, these experiments will make clear the selective pressures that led to the haltere’s evolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.