Department of Psychology, D-12, Regis University, 3333 Regis Blvd., Denver, CO 80221, USA.
Behav Genet. 2010 Mar;40(2):135-45. doi: 10.1007/s10519-009-9328-2.
Although there has been much interest in the relation between brain size and cognition, few studies have investigated this relation within a genetic framework and fewer still in non-adult samples. We analyzed the genetic and environmental covariance between structural MRI data from four brain regions (total brain volume, neocortex, white matter, and prefrontal cortex), and four cognitive measures (verbal IQ (VIQ), performance IQ (PIQ), reading ability, and processing speed), in a sample of 41 MZ twin pairs and 30 same-sex DZ twin pairs (mean age at cognitive test = 11.4 years; mean age at scan = 15.4 years). Multivariate Cholesky decompositions were performed with each brain volume measure entered first, followed by the four cognitive measures. Consistent with previous research, each brain and cognitive measure was found to be significantly heritable. The novel finding was the significant genetic but not environmental covariance between brain volumes and cognitive measures. Specifically, PIQ shared significant common genetic variance with all four measures of brain volume (r (g) = .58-.82). In contrast, VIQ shared significant genetic influence with neocortex volume only (r (g) = .58). Processing speed was significant with total brain volume (r (g) = .79), neocortex (r (g) = .64), and white matter (r (g) = .89), but not prefrontal cortex. The only brain measure to share genetic influence with reading was total brain volume (r (g) = .32), which also shared genetic influences with processing speed.
尽管人们对大脑大小与认知之间的关系很感兴趣，但很少有研究在遗传框架内探讨这种关系，在非成人样本中更是如此。我们分析了来自四个大脑区域（总脑体积、新皮层、白质和前额叶皮层）的结构磁共振成像数据与四项认知测量（言语智商（VIQ）、表现智商（PIQ）、阅读能力和处理速度）之间的遗传和环境协方差，样本包括 41 对同卵双胞胎和 30 对同性别的异卵双胞胎（认知测试的平均年龄=11.4 岁；扫描的平均年龄=15.4 岁）。采用多元 Cholesky 分解，首先输入每个脑容量测量值，然后输入四项认知测量值。与之前的研究一致，每个脑区和认知测量值都被发现具有显著的遗传性。新的发现是脑容量和认知测量值之间存在显著的遗传但非环境协方差。具体来说，PIQ 与四个脑容量测量值都具有显著的共同遗传变异（r (g) =.58-.82）。相比之下，VIQ 仅与新皮层体积具有显著的遗传影响（r (g) =.58）。处理速度与总脑体积（r (g) =.79）、新皮层（r (g) =.64）和白质（r (g) =.89）都具有显著的遗传影响，但与前额叶皮层无关。唯一与阅读具有遗传影响的脑区是总脑体积（r (g) =.32），它也与处理速度具有遗传影响。
