Doctoral Dissertation Research: Behavioral reconstruction and the effects of habitual activity on the bone-muscle interface

骨骼可以提供许多关于运动和行为模式的线索，这种形式-功能关系使骨骼成为重建动物和人类进化史和过去行为的重要数据来源。在这篇论文中，我们将在小鼠和灵长类动物模型中研究骨骼对习惯性活动的反应，以提高我们对Ennoses(骨骼上的肌肉附着位置)的理解，因为骨骼的这一特殊特征与功能的关系尚未完全了解。由于活动引起的末端变化的实验证据将适用于各种学科，包括古人类学、生物学、临床医学和法医学。这项工作产生的所有图像将提供给其他研究人员，以促进进一步的跨学科研究。该项目将支持学生的研究体验，包括针对STEM研究中代表性不足的群体的学生，以及传统和在线公共科学推广活动。使用Ennores重建物种水平的运动模式和个人职业依赖于骨骼通过重塑和新骨积累对机械负荷做出反应的前提。然而，最近的实验研究对肌肉活动对骨骼的影响提出了质疑，并证明运动与末端表面的测量没有关系。这个项目解决了与附着部位生物学有关的方法学问题，采取了多层次的方法来评估末端是否以及如何可以用于行为重建。这项研究的第一部分利用受控和提升跑步和攀登模式的小鼠模型来测试活动增加是否会导致肌肉力量生成能力、骨表面粗糙度、骨沉积率和/或骨横截面几何特性的相应增加。这一目标的结果将被应用于现有的灵长类骨骼样本，以观察不同的运动模式与末端发育的关系。在悬垂灵长类、四足灵长类和两足灵长类中选择与运动相关的末端将通过表面和CT扫描进行检查，以根据活动来确定附着部位的特征模式。对宏观骨表面和其下的力学环境的综合分析将提供对末端区域的全面观察。这些数据将为解释末端形态提供经验基础，长期目标是利用这些结构在灵长类化石上进行非破坏性行为重建。

The skeleton can provide many clues about movement and behavior patterns, and this form-function relationship makes bone an important source of data for reconstructing the evolutionary history and past behaviors of animals and humans. In this dissertation project, the response of bone to habitual activity will be investigated in murine and primate models to improve our understanding of entheses (muscle attachment sites on bone), because the relationship of this particular feature of bone to function is not fully understood. Experimental evidence of enthesis change due to activity will be applicable across a variety of disciplines, including paleoanthropology, biology, clinical medicine and forensic science. All images generated as a result of this work will be made available to other researchers in order to promote further interdisciplinary research. The project will support student research experiences, including for students from groups underrepresented in STEM research, and both traditional and online public science outreach activities.The use of entheses to reconstruct species-level locomotor patterns and individual occupation relies on the premise that bone responds to mechanical loading with remodeling and the accumulation of new bone. However, recent experimental studies have questioned the assumed effect of muscle activity on bone and demonstrated no relationship between exercise and measures of the entheseal surface. This project addresses the methodological issues concerning attachment site biology, taking a multilevel approach to assess if and how entheses can be used for behavioral reconstruction. The first component of this study utilizes a murine model with controlled and elevated running and climbing regimes to test whether increased activity results in corresponding increases to muscle force-generating capacity, bone surface roughness, bone depositional rate, and/or bone cross-sectional geometric properties. The results of this aim will then be applied to an existing sample of primate skeletons in order to observe how different locomotor modes relate to enthesis development. A selection of locomotor-relevant entheses in suspensory, quadrupedal and bipedal primates will be examined with surface and CT scans for patterns of attachment site characteristics by activity. A combined analysis of the macroscopic bone surface and its underlying mechanical environment will provide a comprehensive view of the enthesis region. These data will provide an empirical foundation for the interpretation of enthesis morphology, with the long-term goal of enabling non-destructive behavioral reconstruction on fossil primates using these structures.