Doctoral Dissertation Research: Encephalic Arterial Canals and their Functional Significance

进化一个像人脑这样的大大脑的成本被假设为需要能量权衡，因此大脑新陈代谢的增加可能需要减少用于生长和繁殖的能量。然而，为了更好地研究这些潜在的权衡，还需要更多关于大脑新陈代谢(能量使用率)的比较数据。因为对于大多数活着的物种来说，直接测量是困难的，而对于灭绝的物种是不可能的，这个博士论文项目将使用从受大脑代谢需求影响的骨骼特征获得的测量来推断广泛的哺乳动物群体的大脑新陈代谢速率。比较哺乳动物在大脑中消耗的能量相对于身体新陈代谢的差异的方式和原因，将有助于增进对灵长类和人类生物学以及大脑进化的了解。该项目将生成大量的3D头骨扫描，用于杜克大学和北卡罗来纳自然科学博物馆的学生指导和公共宣传。这些数据还将在数字档案馆MorPhoSource上发布，供公众查阅，这将产生进一步的研究和教育用途。以前的研究表明，传输大脑动脉的孔的大小可能被用来预测真首领动物的大脑葡萄糖利用率。该项目旨在进一步评估使用这些孔来测试大脑大小进化的能量假说。横孔(传递椎动脉)和颈动脉管(传递颈内动脉)的直径将分别从高分辨率计算机断层扫描获得的骨学和3-D数字化标本中测量，这些标本来自有袋类、神经胶质类、泡囊类、异种动物和一些食肉动物的广泛分类样本。为了进一步阐明骨孔大小、脑大小和脑代谢之间的关系，还将对人类身体骨学样本中的骨管面积和通过个体发育预测的血流速度变化进行研究。利用这些数据，该项目将测试灵长类和其他哺乳动物的大脑在多大程度上通过提高身体的代谢率来维持。这项研究将在哺乳动物大脑进化的背景下进一步理解人脑进化。这一奖项反映了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。

The cost of evolving a large brain, like the human brain, is hypothesized to require energetic trade-offs, such that increases in brain metabolism may require reductions in energy used for growth and reproduction. However, additional comparative data on brain metabolism (the rate at which energy is used) are needed to better investigate these potential trade-offs. Because direct measurements are difficult to obtain for most living species and impossible for extinct ones, this doctoral dissertation project will use measurements obtained from skeletal features affected by brain metabolic demands to infer rates of brain metabolism in a broad group of mammals. Comparing how and why mammals may vary in the energy they expend on the brain relative to their body's metabolism will advance knowledge in primate and human biology and brain evolution. This project will generate numerous 3D scans of skulls that will be used for student mentoring and public outreach at Duke University and the North Carolina Museum of Natural Sciences. These data will also be released for public access on the digital archive MorphoSource, which will yield further research and educational utility.Previous studies suggest that the size of foramina that transmit the brain's arteries may be used to predict brain glucose utilization rates in euarchontans. This project aims to further evaluate the use of these foramina to test energetic hypotheses of brain size evolution. Diameters of the transverse foramina (which transmit the vertebral artery) and carotid canals (which transmit the internal carotid artery) will be measured from osteological and 3-D digitized specimens obtained from high-resolution computed tomography scans, respectively, in a broad taxonomic sample of marsupials, glirans, afrotheres, xenarthrans, and some carnivorans. A study of bony canal area and predicted blood flow rate change through ontogeny in a cadaveric osteological sample of humans will also be conducted to further elucidate the relationship between foramen size, brain size, and brain metabolism. Using these data, this project will test the extent to which large brains in primates and other mammals are sustained by increasing the body's metabolic rate. This research will further the understanding of human brain evolution within the context of mammalian brain 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.