Doctoral Dissertation Research: Encephalic Arterial Canals and their Functional Significance

据推测，进化出一个像人类大脑这样的大大脑的代价是需要能量上的权衡，比如大脑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，还需要更多关于脑代谢（能量消耗的速率）的比较数据。由于对大多数现存物种的直接测量很难获得，而对灭绝的物种则不可能获得，因此本博士论文项目将使用从受脑代谢需求影响的骨骼特征中获得的测量结果来推断广泛哺乳动物的脑代谢率。比较哺乳动物消耗在大脑上的能量相对于身体新陈代谢的方式和原因可能会有所不同，这将推进灵长类动物和人类生物学以及大脑进化方面的知识。该项目将生成大量的头骨3D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。这些数据也将在数字档案MorphoSource上发布，供公众访问，这将产生进一步的研究和教育效用。先前的研究表明，传递大脑动脉的孔的大小可能被用来预测等巨噬动物的脑葡萄糖利用率。该项目旨在进一步评估这些孔的使用，以测试大脑大小进化的能量假说。横向孔（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3d数字化标本中测量，这些标本来自有袋类动物、胶质类动物、非洲动物、异种动物和一些食肉动物的广泛分类样本。我们还将对人类尸体骨骼样本进行骨管面积和个体发生预测血流速率变化的研究，以进一步阐明孔大小、脑大小和脑代谢之间的关系。利用这些数据，该项目将测试灵长类动物和其他哺乳动物的大脑在多大程度上是通过增加身体的代谢率来维持的。这项研究将在哺乳动物大脑进化的背景下进一步了解人类大脑的进化。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。

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.