Doctoral Dissertation Research: Human memory, adult neurogenesis, and the evolution of the hippocampus

海马体是一种对长期记忆的储存和回忆以及空间导航至关重要的大脑结构。它也是在人的一生中保持产生新神经元能力的唯一大脑结构之一，这是有效的长期记忆所必需的特征。该项目将通过在神经解剖学、基因表达和遗传学水平上将人类的海马体与我们最亲近的非人类灵长类动物的海马体进行比较，来研究人类记忆的起源。这项研究将为某些人类特定记忆相关能力的神经生物学基础以及可能推动其出现的生态因素提供新的见解。此外，该项目将确定可能使人类特别容易受到某些已知影响海马体的神经疾病和紊乱（例如，阿尔茨海默病、自闭症谱系障碍）影响的神经生物学靶点。这个项目的数据可以为进一步研究和发现人类大脑的形态和功能提供信息。该项目将支持本科生指导和研究经验，研究人员将参与公共科学推广，以促进对神经科学、遗传学和人类进化的理解。虽然海马体对所有哺乳动物的长期记忆都至关重要，但只有人类的海马体还能调节情景记忆，即回忆特定个人经历和想象未来事件的能力。这可能首先在我们的人类祖先中出现，以满足日益具有挑战性的环境，扩大的家园范围和新的狩猎/觅食策略的需求。最近的证据表明，与其他灵长类动物相比，人类的整个海马体在相对大小、神经元结构和分布以及基因表达方面已经进化得更加特化。然而，众所周知，海马体是由分子和功能上不同的子区组成的。因此，该项目将从神经解剖学、基因表达和基因型方面研究人类和非人类灵长类动物海马的进化。海马亚区的体积比例和成人海马神经发生的程度将被估计，生态变量将与神经解剖学测量相关联，以测试神经生态学关系。将生成海马亚区全转录组基因表达数据，并用于鉴定人类差异表达的基因。基因的蛋白质编码和调控区域将进行阳性选择测试。

The hippocampus is a brain structure that is critical for the storage and recall of long-term memory as well as spatial navigation. It is also one of the only brain structures that maintains the ability to generate new neurons throughout one's lifetime, a feature necessary for effective long-term memory. This project will investigate the origins of human memory by comparing the hippocampus of humans to those of our closest living non-human primate relatives at the levels of neuroanatomy, gene expression, and genetics. This research will provide novel insights into the neurobiological basis of certain human-specific memory-related abilities and the ecological factors that may have driven their emergence. Furthermore, this project will identify neurobiological targets that may render humans uniquely susceptible to certain neurological diseases and disorders known to affect the hippocampus (e.g., Alzheimer's disease, Autism spectrum disorder). Data from this project may inform further research and discoveries on human brain form and function. The project will support undergraduate mentoring and research experiences, and the investigators will engage in public science outreach to promote understanding of neuroscience, genetics and human evolution.While the hippocampus is central to long-term memory in all mammals, only in humans is it known to additionally mediate episodic memory, the capacity to recall specific personal experiences and imagine future events. This may have first emerged in our hominin ancestors to meet the demands of increasingly challenging environments, expanded home ranges, and novel hunting/foraging strategies. Recent evidence suggests that the human whole-hippocampus has become evolutionarily specialized compared to those of other primates in terms of relative size, neuronal structure and distribution, and gene expression. However it is well known that the hippocampus is composed of molecularly and functionally distinct subfields. This project will therefore investigate the evolution of the hippocampus in humans and non-human primates in terms of neuroanatomy, gene expression, and genotype. Volumetric proportions of hippocampal subfields and degree of adult hippocampal neurogenesis will be estimated, and ecological variables will be correlated with neuroanatomical measures to test for neuroecological relationships. Whole-transcriptome gene expression data of hippocampal subfields will be generated and used to identify genes that are differentially expressed in humans. Protein-coding and regulatory regions of genes will be tested for positive selection.