Department of Computer Science, University of California, Santa Barbara, CA 93106, USA.
Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106, USA.
Neuroimage. 2018 May 15;172:390-403. doi: 10.1016/j.neuroimage.2018.01.050. Epub 2018 Feb 2.
We present a method to discover differences between populations with respect to the spatial coherence of their oriented white matter microstructure in arbitrarily shaped white matter regions. This method is applied to diffusion MRI scans of a subset of the Human Connectome Project dataset: 57 pairs of monozygotic and 52 pairs of dizygotic twins. After controlling for morphological similarity between twins, we identify 3.7% of all white matter as being associated with genetic similarity (35.1 k voxels, p<10, false discovery rate 1.5%), 75% of which spatially clusters into twenty-two contiguous white matter regions. Furthermore, we show that the orientation similarity within these regions generalizes to a subset of 47 pairs of non-twin siblings, and show that these siblings are on average as similar as dizygotic twins. The regions are located in deep white matter including the superior longitudinal fasciculus, the optic radiations, the middle cerebellar peduncle, the corticospinal tract, and within the anterior temporal lobe, as well as the cerebellum, brain stem, and amygdalae. These results extend previous work using undirected fractional anisotrophy for measuring putative heritable influences in white matter. Our multidirectional extension better accounts for crossing fiber connections within voxels. This bottom up approach has at its basis a novel measurement of coherence within neighboring voxel dyads between subjects, and avoids some of the fundamental ambiguities encountered with tractographic approaches to white matter analysis that estimate global connectivity.
我们提出了一种方法，可以发现人群之间在其定向白质微观结构的空间一致性方面的差异，这些人群的白质区域形状任意。该方法应用于人类连接组计划数据集的一个子集的弥散 MRI 扫描：57 对同卵双胞胎和 52 对异卵双胞胎。在控制双胞胎之间的形态相似性之后，我们确定了 3.7%的所有白质与遗传相似性相关（35.1k 体素，p<10，错误发现率 1.5%），其中 75%的空间聚类到二十二个连续的白质区域。此外，我们表明这些区域内的方向相似性可以推广到 47 对非双胞胎兄弟姐妹的子集，并且表明这些兄弟姐妹的平均相似性与异卵双胞胎相似。这些区域位于深部白质中，包括上纵束、视辐射、小脑中脚、皮质脊髓束以及前颞叶内部，以及小脑、脑干和杏仁核。这些结果扩展了以前使用无向分数各向异性测量白质中潜在可遗传影响的工作。我们的多方向扩展更好地解释了体素内交叉纤维连接。这种自下而上的方法基于一种新颖的测量方法，即在主体之间相邻体素对偶之间测量相干性，并且避免了一些在用于白质分析的轨迹方法中遇到的基本歧义，这些方法估计全局连通性。
