Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA.
Cereb Cortex. 2009 Nov;19(11):2728-35. doi: 10.1093/cercor/bhp026. Epub 2009 Mar 18.
Neuroimaging studies examining the effects of aging and neuropsychiatric disorders on the cerebral cortex have largely been based on measures of cortical volume. Given that cortical volume is a product of thickness and surface area, it is plausible that measures of volume capture at least 2 distinct sets of genetic influences. The present study aims to examine the genetic relationships between measures of cortical surface area and thickness. Participants were men in the Vietnam Era Twin Study of Aging (110 monozygotic pairs and 92 dizygotic pairs). Mean age was 55.8 years (range: 51-59). Bivariate twin analyses were utilized in order to estimate the heritability of cortical surface area and thickness, as well as their degree of genetic overlap. Total cortical surface area and average cortical thickness were both highly heritable (0.89 and 0.81, respectively) but were essentially unrelated genetically (genetic correlation = 0.08). This pattern was similar at the lobar and regional levels of analysis. These results demonstrate that cortical volume measures combine at least 2 distinct sources of genetic influences. We conclude that using volume in a genetically informative study, or as an endophenotype for a disorder, may confound the underlying genetic architecture of brain structure.
神经影像学研究考察了衰老和神经精神障碍对大脑皮层的影响，这些研究主要基于皮质体积的测量。由于皮质体积是厚度和表面积的产物，因此体积测量至少可以捕捉到 2 组不同的遗传影响是合理的。本研究旨在检验大脑表面积和厚度测量值之间的遗传关系。参与者是越南时代老化双胞胎研究中的男性（110 对同卵双胞胎和 92 对异卵双胞胎）。平均年龄为 55.8 岁（范围：51-59 岁）。为了估计大脑表面积和厚度的遗传率以及它们的遗传重叠程度，我们利用了双变量双胞胎分析。总大脑表面积和平均大脑皮层厚度都具有高度遗传性（分别为 0.89 和 0.81），但在遗传上基本无关（遗传相关系数为 0.08）。在大脑叶和区域分析水平上，这种模式是相似的。这些结果表明，体积测量值结合了至少 2 种不同的遗传影响来源。我们得出结论，在遗传信息丰富的研究中使用体积，或者将其作为疾病的内表型，可能会混淆大脑结构的潜在遗传结构。
