Collaborative Research: Unraveling the Deep History of Avian Neurological Complexity: Implications for the Origins of Flight and Organization of the Modern Avian Brain

尽管对大脑功能的了解有所进步，但大脑进化与生态多样性之间的关系仍然知之甚少。一个突出的例子就是鸟类。飞向空中使鸟类的恐龙祖先能够利用一系列生态位，这些生态位构成了鸟类惊人的现代多样性（大约有1万种现存物种）。这种进化成功的一个重要部分可能源于相对较大的大脑的发展，这被认为是协调动力飞行的各种微妙组成部分所必需的。这项研究通过跨学科的方法来了解鸟类及其恐龙亲戚复杂的神经进化，从而补充了NSF BRAIN计划。为此，采用了一系列新技术和现有技术的新应用来记录与动力飞行起源有关的大脑的主要变化。这项研究还将建立一个大脑扩张的模型，以补充已有的哺乳动物模型。结果将是一个前所未有的鸟类脑解剖数据库，不仅包括形态学系统的图像，还包括它们与通过脑功能生成的数据的关系。神经解剖学，认知和行为进化之间的关系仍然知之甚少，特别是在深时间和整个脊椎动物生命树中。本研究通过跨学科的研究，探讨了现存鸟类的大大脑与标志着从跑动（奔跑）恐龙向飞行鸟类过渡的形态变化之间的进化联系。最初的步骤是使用创新的成像方法和新的染色技术来产生关于鸟类在飞行时使用大脑哪些区域的第一批数据，以及这种活动与其他行为有何不同。这些数据将作为一个广泛分析现存鸟类脑化（头部增大）的框架，并沿着鸟类飞行起源的谱系进行分析。共享地标将用于将颅内腔细分为功能相关的分区，允许测试个体神经结构之间的体积大小变化，包括飞行中最活跃的神经结构。本研究还将使用几何形态计量学（解剖学比较）来评估神经解剖分区之间的共变，从而评估大脑功能和/或进化上整合区域的存在。简而言之，拟议的研究将产生关于鸟类如何使用大脑的数据，并将这些数据用于更好地理解大脑进化与高度衍生的鸟类身体计划起源之间的古老关系。

Despite advances in knowledge of brain function, the relationship between brain evolution and ecological diversity remains poorly known. A prominent example is that of birds. Taking to the air enabled the dinosaurian ancestors of birds to exploit a range of ecological niches that now underlie the remarkable modern diversity of the group (approximately 10,000 living species). A significant part of this evolutionary success may have stemmed from the development of a relatively large brain, which has been considered necessary for coordinating the various, nuanced components of powered flight. This study complements the NSF BRAIN initiative by using a cross-disciplinary approach to understand the complex neurological evolution of birds and their dinosaurian relatives. To that end, an array of new techniques and new applications of existing technologies are employed to document the major changes in the brain associated with the origin of powered flight. This study also will establish a model of brain expansion complementing that already available for mammals. The outcome will be an unprecedented database of avian brain anatomy that includes not only imagery of morphological systems but also their relation to data generated through brain function. The relationship between neuroanatomical, cognitive and behavioral evolution remains poorly understood, especially in deep time and across the vertebrate tree of life. This study addresses this relationship using a cross-disciplinary investigation of the evolutionary link between the large brain of living birds and the morphological changes that mark the transition from cursorial (running) dinosaur to flying bird. Initial steps use innovative imaging methods and novel staining techniques to generate the first data on what areas of the brain birds use while flying, and how this activity differs from that of other behaviors. These data will serve as a framework for a broad analysis of encephalization (increasing head size) within living birds and along the lineage where avian flight originated. Shared landmarks will be used to subdivide the endocranial cavity into functionally relevant partitions that allow testing for volumetric size changes between individual neural structures, including those most active during flight. This study also will use geometric morphometrics (anatomical comparisons) to assess covariation between neuroanatomical partitions and thus the presence of functionally and/or evolutionarily integrated regions of the brain. In short, the proposed study will generate data on how birds use their brain and apply those data to better understand the ancient relationship between brain evolution and the origin of the highly derived avian body plan.