Department of Psychology & Neuroscience, Duke University, Box 104410, Durham, NC, USA.
Department of Population Health Sciences, Duke University School of Medicine, Durham, NC, USA.
Cereb Cortex. 2019 Jul 22;29(8):3496-3504. doi: 10.1093/cercor/bhy219.
People who score higher on intelligence tests tend to have larger brains. Twin studies suggest the same genetic factors influence both brain size and intelligence. This has led to the hypothesis that genetics influence intelligence partly by contributing to the development of larger brains. We tested this hypothesis using four large imaging genetics studies (combined N = 7965) with polygenic scores derived from a genome-wide association study (GWAS) of educational attainment, a correlate of intelligence. We conducted meta-analysis to test associations among participants' genetics, total brain volume (i.e., brain size), and cognitive test performance. Consistent with previous findings, participants with higher polygenic scores achieved higher scores on cognitive tests, as did participants with larger brains. Participants with higher polygenic scores also had larger brains. We found some evidence that brain size partly mediated associations between participants' education polygenic scores and their cognitive test performance. Effect sizes were larger in the population-based samples than in the convenience-based samples. Recruitment and retention of population-representative samples should be a priority for neuroscience research. Findings suggest promise for studies integrating GWAS discoveries with brain imaging to understand neurobiology linking genetics with cognitive performance.
智商测试得分较高的人往往大脑较大。双胞胎研究表明，相同的遗传因素既影响大脑大小又影响智力。这导致了一个假设，即遗传通过促进大脑更大的发育在一定程度上影响智力。我们使用四项来自教育程度全基因组关联研究（GWAS）的多基因分数的大型成像遗传学研究（合并 N=7965）来检验这一假设，教育程度是智力的一个相关因素。我们进行了荟萃分析，以检验参与者的遗传学、总脑容量（即大脑大小）和认知测试表现之间的关联。与先前的发现一致，多基因分数较高的参与者在认知测试中得分较高，大脑较大的参与者也是如此。多基因分数较高的参与者大脑也较大。我们发现了一些证据表明，大脑大小部分解释了参与者的教育多基因分数与他们的认知测试表现之间的关联。基于人群的样本中的效应大小大于基于便利的样本。招募和保留具有代表性的人群样本应该是神经科学研究的优先事项。这些发现为将 GWAS 发现与大脑成像相结合的研究提供了希望，这些研究旨在了解将遗传与认知表现联系起来的神经生物学。
