An advanced surgical microscope for novel studies of sensorimotor integration for flight control

大脑的一个关键作用是合成感官信息来控制运动。大多数神经科学研究都是在受限的准备中进行的，这在我们对自由运动所需的复杂运动的控制方面留下了一个重大的空白。机动性对生存至关重要，而且容易受到疾病、伤害和衰老的影响。我的实验室团队使用蜂鸟和斑马雀作为研究模型，因为它们清晰的视觉路径和极具机动性的飞行可以在实验环境中进行研究。我们现在正在使用新技术来研究自由飞行的鸟类的大脑，这在以前是不可能的。然而，我们缺少一种基本的设备，一台现代的手术显微镜。 在最近的研究中，我的团队研究了视觉信号是如何在大脑中处理并转化为基本控制任务的运动命令的，这些基本控制任务包括速度、居中、减速、避障、群体行为(群集)和停留(悬停)。通过之前的RTI拨款，我们开发了一个集成的飞行竞技场，包括3D轨迹的自动飞行跟踪，实时闭环视觉刺激演示，以及允许电子设备与飞鸟一起飞行以同时进行电生理记录和光遗传激活的移动轨迹。世界上没有其他实验室具备这些能力。我们工作面临的一个重大挑战是，我们的大楼或部门没有可用的现代外科显微镜。这两种现有的望远镜可以追溯到上个世纪中叶，它们的光学分辨率、照明和控制能力都很差。 要制造用于使用四极管记录和光遗传刺激的慢性植入物，需要一台最先进的外科显微镜，它具有四个基本特征：1)扩展景深的高分辨率光学；2)用于深腔光学分辨率的定向光源；3)免提光学控制；4)稳定的定位和灵活的6轴可操作性，以应对电线、电缆和视觉监视器在动物对象周围的移动。为了便于有效地将专业技能传授给总部，示波器还需要录像和展示，以及一名助理的目标。 现代手术显微镜将允许对控制复杂运动的神经回路进行研究，否则这项研究是不可能的。指导这项工作的三个具体问题是：a)孤飞和群飞如何编码其他鸟类的运动，无论是在物体运动视觉通路中还是在光流视觉通路中？b)主要的光流核如何对前进运动的不同制导算法进行编码？c)悬停和前飞之间的不同制导算法是由光流信号的传出复制抑制调节的吗？

A key role of the brain is to synthesize sensory information for the control of movement. Most neuroscience research occurs in restricted preparations, which leaves a major gap in our understanding of the control of complex motions required for free movement. Maneuverability is critical for survival, and susceptible to disease, injury, and ageing. My laboratory group uses hummingbirds and zebra finches as research models because their well-defined visual pathways and extremely maneuverable flight can be studied in an experimental setting. We are now using new technologies to study the brain in freely flying birds, something which was not previously possible. However, we lack one essential piece of equipment, a modern surgical microscope. In recent studies, my group investigated how visual signals are processed in the brain and transformed into motor commands for fundamental control tasks including velocity, centering, decelerating, obstacle avoidance, group behaviour (flocking), and holding station (hovering). Through a previous RTI grant, we developed an integrated flight arena that includes automated flight tracking of 3D trajectories, real-time closed-loop visual stimulus presentation, and a moving track that allows electronics to travel with the flying bird for simultaneous electrophysiological recording and optogenetic activation. There is no other laboratory in the world with these capabilities. A significant challenge to our work is that there are no modern surgical microscopes available in our building or department. The two available scopes date from the middle of the last century and have poor optical resolution, lighting, and control. The ability to make chronic implants for employing tetrode recordings and optogenetic stimulation requires a state-of-the-art surgical microscope that has four essential features: 1) high resolution optics over an extended depth of field, 2) directed light sources for optical resolution in deep cavities, 3) hands-free optical control, and 4) stable positioning and flexible 6-axis maneuverability to cope with the movement of wires, cables, and visual monitors around an animal subject. To facilitate the efficient transmission of skill for expertise to HQP, the scope also requires video recording and display, and an assistant's objective. A modern surgical scope will allow for investigation of the neural circuits that control complex locomotion, research that is not otherwise possible. Three specific questions that will guide this work are: a) how do solitary versus social flyers encode the motion of other birds, whether in the object motion visual pathway or in the optic flow visual pathway?; b) how do the major optic flow nuclei contribute to the encoding of distinct guidance algorithms for forward motion?; c) are distinct guidance algorithms between hovering and forward flight mediated by efference copy suppression of optic flow signals?