Musculoskeletal modeling and simulation of hominin bipedal locomotion

该奖项是美国国家科学基金会社会、行为和经济科学博士后研究奖学金（SPRF）计划的一部分。SPRF计划的目标是为学术界、工业界或私营部门和政府的科学事业准备有前途的早期职业博士级科学家。SPRF奖励包括在知名科学家的赞助下进行为期两年的培训，并鼓励博士后进行独立研究。美国国家科学基金会寻求促进科学界各阶层的科学家，包括那些未被充分代表的群体的科学家，参与其研究项目和活动；博士后阶段被认为是实现这一目标的一个重要的专业发展阶段。每个博士后必须解决各自学科领域的重要科学问题。在洛杉矶加州州立大学的阿什利·希斯博士的赞助下，这个博士后奖学金奖支持一位早期职业科学家创建一个计算机模拟人类祖先如何行走。虽然用两只脚走路看起来很平常，但这种非凡的能力比人类其他独特的特征（包括大脑）更早出现，并将我们和我们的化石血统与其他灵长类动物区分开来。所有的人类祖先化石都显示出用两只脚走路的迹象，但有几个物种，比如320万年前的南方古猿阿法种，可能更像直立的黑猩猩，而不是现代人类，或者以一种独特的方式行走。生物力学建模和模拟是定量严谨的方法，具有解决这类不确定性的独特能力。建模和仿真允许研究人员创建逼真的三维肌肉骨骼模型，其解剖参数可以单独操纵，以明确检查形式-功能关系。通过建立阿法南方古猿的肌肉骨骼模型，并将人类和黑猩猩的数据参数括起来，该项目将探索阿法南方古猿能够像黑猩猩一样、像人类一样或独特的介于两者之间的两足行走的假设，并结合积极、稳定或消极的选择。肌肉骨骼模型和模拟已经被用于评估古人类运动的某些方面，但是基于最新重建的系统发育方框模型尚未被创建或在古人类学背景下进行测试。该项目将提高我们对人类进化过程中“马赛克”、“原型”或“过渡”分类群的运动潜力的理解，并可以为进化情景提供信息，这不仅会影响古人类学，也会影响进化生物学。该项目还将为未来的假设检验提供数据，使研究人员能够探索南方古猿阿法种的运动如何与环境、饮食和社会行为等古生物变量相关。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。

This award was provided as part of NSF's Social, Behavioral and Economic Sciences Postdoctoral Research Fellowships (SPRF) program. The goal of the SPRF program is to prepare promising, early career doctoral-level scientists for scientific careers in academia, industry or private sector, and government. SPRF awards involve two years of training under the sponsorship of established scientists and encourage Postdoctoral Fellows to perform independent research. NSF seeks to promote the participation of scientists from all segments of the scientific community, including those from underrepresented groups, in its research programs and activities; the postdoctoral period is considered to be an important level of professional development in attaining this goal. Each Postdoctoral Fellow must address important scientific questions that advance their respective disciplinary fields. Under the sponsorship of Dr. Ashley Heers at California State University, Los Angeles, this postdoctoral fellowship award supports an early career scientist creating a computer simulation of how human ancestors may have walked. While walking on two feet may seem mundane, this remarkable ability predates other uniquely human qualities, including a large brain, and separates us and our fossil lineage from other primates. All fossil human ancestors show some indication of walking on two feet, but several species, like 3.2 million-year-old Australopithecus afarensis, may have walked more like an upright chimpanzee than a modern human, or in a unique way all together.Biomechanical modeling and simulation are quantitatively rigorous methods that have the unique ability to address this type of uncertainty. Modeling and simulation allow researchers to create realistic three-dimensional musculoskeletal models whose anatomical parameters can be individually manipulated to explicitly examine form-function relationships. By creating a musculoskeletal model of A. afarensis and bracketing parameters with data on humans and chimpanzees, this project will explore the hypotheses that A. afarensis was capable of chimp-like, human-like, or uniquely in-between bipedal walking, in conjunction with positive, stabilizing, or negative selection. Musculoskeletal modeling and simulation have previously been used to assess certain aspects of hominin locomotion, but a phylogenetically bracketed model based on the most up-to-date reconstructions has not yet been created or tested in a paleoanthropological context. This project will improve our understanding of locomotor potential in “mosaic”, “proto”, or “transitional” taxa during human evolution, and can inform evolutionary scenarios that will impact not only paleoanthropology, but also evolutionary biology. This project will also introduce data for future hypothesis testing, allowing researchers to explore how the locomotion of A. afarensis might have related to paleobiological variables like environment, diet, and social behavior.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.