Doctoral Dissertation Research: Musculoskeletal Craniofacial Evolution and Developmental Plasticity

这篇博士论文研究项目考察了早期断奶对发育中的头面部复合体肌肉和骨骼组织进化的影响。现代人类的头面部复合体已经进化得越来越小，脸中部变短，脑形状呈球形，这些特征与饮食和咀嚼的变化有关。以前在比较材料和化石材料中使用骨骼进行的这一主题的调查存在方法论上的局限性。在这里，一种最先进的成像方法的新组合被用来分析颅面发育过程中骨骼和软组织的变化。这项研究有可能为公共卫生研究提供有关早期生命发展的信息。该项目促进了STEM的学生培训和指导，并通过出版物、演示文稿和公开可用的成像数据库传播产生的数据。该项目使用一个细格化的比较模型来检验早期和典型断奶对肌肉骨骼颅面发育的影响。本项目的具体目的是描述(1)颅面紧张化和(2)早期断奶对早期口腔运动技能发展阶段肌肉骨骼性能、整体性和对称性的影响。以前的研究主要集中在骨骼组织的变化上，主要是由于标准CT中可见的内容和化石记录中保存的内容的局限性。在这个项目中使用了一种新的对比增强微型计算机断层扫描(Micro-CT)方法的组合来分析骨、肌肉和软骨的个体发育系列。这一多层次的研究设计融合了进化、行为、形态和功能理论，使人们能够更好地了解功能和组织相互作用对颅面复合体肌肉骨骼发育的影响。此外，该项目可以提高我们对高度可塑性早期生命阶段头面部复合体中形式-功能相互关系的理解，并对人类进化过程中的行为适应和成长轨迹产生影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This doctoral dissertation research project examines the effects of early weaning on the evolution of the muscles and skeletal tissue in the developing craniofacial complex. The modern human craniofacial complex has evolved to become smaller, with shorter midface and globular brain shape, characteristics linked to changes in diet and chewing. Previous investigations of this topic using bone in comparative and fossil materials have methodological limitations. Here, a novel combination of state-of-the-art imaging methods is used to analyze changes in bone and soft tissues during craniofacial development. The research has the potential to inform public health research on early life development. The project fosters student training and mentoring in STEM, and resulting data are disseminated through publications, presentations, and publicly available imaging databases. The project uses a gracilized comparative model to examine the influence of early and typical weaning on musculoskeletal craniofacial development. The specific aims of this project are to characterize the effects of (1) craniofacial gracilization and (2) early weaning on musculoskeletal performance, integration, and symmetry during the stages of oral motor skill development in early life. Previous research has focused on changes in skeletal tissue, primarily due to limitations in what is visible in a standard CT and what is preserved in the fossil record. A novel combination of contrast enhanced micro-computed tomography (micro-CT) methods is used in this project to analyze ontogenetic series of bone, muscle, and cartilage. This multilevel research design incorporates evolutionary, behavioral, morphological, and functional theories, allowing greater understanding of the impact of function and tissue interactions on the musculoskeletal development in the craniofacial complex. Furthermore, this project can improve our understanding of the form-function interrelationships in the craniofacial complex during highly plastic early life stages, with implications for behavioral adaptations and growth trajectories during human 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.