Department of Radiology, University of California, San Diego, La Jolla, California 92093-0738, USA.
Biol Psychiatry. 2010 Mar 1;67(5):493-9. doi: 10.1016/j.biopsych.2009.09.032. Epub 2009 Dec 6.
Although global brain structure is highly heritable, there is still variability in the magnitude of genetic influences on the size of specific regions. Yet, little is known about the patterning of those genetic influences, i.e., whether the same genes influence structure throughout the brain or whether there are regionally specific sets of genes.
We mapped the heritability of cortical thickness throughout the brain using three-dimensional structural magnetic resonance imaging in 404 middle-aged male twins. To assess the amount of genetic overlap between regions, we then mapped genetic correlations between three selected seed points and all other points comprising the continuous cortical surface.
There was considerable regional variability in the magnitude of genetic influences on cortical thickness. The primary visual (V1) seed point had strong genetic correlations with posterior sensory and motor areas. The anterior temporal seed point had strong genetic correlations with anterior frontal regions but not with V1. The middle frontal seed point had strong genetic correlations with inferior parietal regions.
These results provide strong evidence of regionally specific patterns rather than a single, global genetic factor. The patterns are largely consistent with a division between primary and association cortex, as well as broadly defined patterns of brain gene expression, neuroanatomical connectivity, and brain maturation trajectories, but no single explanation appears to be sufficient. The patterns do not conform to traditionally defined brain structure boundaries. This approach can serve as a step toward identifying novel phenotypes for genetic association studies of psychiatric disorders and normal and pathological cognitive aging.
尽管全球大脑结构具有高度遗传性，但特定区域大小的遗传影响程度仍存在差异。然而，人们对这些遗传影响的模式知之甚少，即相同的基因是否会影响整个大脑的结构，或者是否存在区域特异性的基因集。
我们使用三维结构磁共振成像在 404 名中年男性双胞胎中绘制了整个大脑皮质厚度的遗传性。为了评估区域之间遗传重叠的程度，我们然后绘制了三个选定的种子点与构成连续皮质表面的所有其他点之间的遗传相关性。
皮质厚度的遗传影响程度存在相当大的区域变异性。主要视觉（V1）种子点与后感觉和运动区具有很强的遗传相关性。前颞叶种子点与前额叶区域具有很强的遗传相关性，但与 V1 没有相关性。中间额种子点与下顶叶区域具有很强的遗传相关性。
这些结果提供了区域特异性模式而不是单一的全球遗传因素的有力证据。这些模式在很大程度上与初级和联合皮层的划分以及广泛定义的脑基因表达、神经解剖连接和脑成熟轨迹一致，但没有一个单一的解释似乎足够。这些模式不符合传统定义的脑结构边界。这种方法可以作为识别精神障碍和正常及病理性认知衰老的遗传关联研究中新型表型的一步。
