Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea.
Seoul National University Hospital, Seoul, Republic of Korea.
Biomed Res Int. 2020 Aug 11;2020:3560259. doi: 10.1155/2020/3560259. eCollection 2020.
The current study examined gender-related differences in hemispheric asymmetries of graph metrics, calculated from a cortical thickness-based brain structural covariance network named hemispheric morphological network.
Using the T1-weighted magnetic resonance imaging scans of 285 participants (150 females, 135 males) retrieved from the Human Connectome Project (HCP), hemispheric morphological networks were constructed per participant. In these hemispheric morphologic networks, the degree of similarity between two different brain regions in terms of the distributed patterns of cortical thickness values (the Jensen-Shannon divergence) was defined as weight of network edge that connects two different brain regions. After the calculation and summation of global and local graph metrics (across the network sparsity levels = 0.10-0.36), asymmetry indexes of these graph metrics were derived.
Hemispheric morphological networks satisfied small-worldness and global efficiency for the network sparsity ranges of = 0.10-0.36. Between-group comparisons (female versus male) of asymmetry indexes revealed opposite directionality of asymmetries (leftward versus rightward) for global metrics of normalized clustering coefficient, normalized characteristic path length, and global efficiency (all < 0.05). For the local graph metrics, larger rightward asymmetries of cingulate-superior parietal gyri for nodal efficiency in male compared to female, larger leftward asymmetry of temporal pole for degree centrality in female compared to male, and opposite directionality of interhemispheric asymmetry of rectal gyrus for degree centrality between female (rightward) and male (leftward) were shown (all < 0.05).
Patterns of interhemispheric asymmetries for cingulate, superior parietal gyrus, temporal pole, and rectal gyrus are different between male and female for the similarities of the cortical thickness distribution with other brain regions. Accordingly, possible effect of gender-by-hemispheric interaction has to be considered in future studies of brain morphology and brain structural covariance networks.
本研究考察了基于皮质厚度的脑结构协变网络（称为半球形态网络）的图形度量的半球间不对称性中的性别差异。
使用从人类连接组计划（HCP）中获取的 285 名参与者（150 名女性，135 名男性）的 T1 加权磁共振成像扫描，为每位参与者构建半球形态网络。在这些半球形态网络中，两个不同脑区之间皮质厚度值分布模式相似性的程度（杰逊-香农散度）被定义为连接两个不同脑区的网络边的权重。在计算和汇总全局和局部图形度量（跨越网络稀疏度水平 = 0.10-0.36）后，得出这些图形度量的不对称指数。
半球形态网络在网络稀疏度范围为 = 0.10-0.36 时满足小世界和全局效率。不对称指数的组间比较（女性与男性）显示全局度量的归一化聚类系数、归一化特征路径长度和全局效率的不对称方向相反（均<0.05）。对于局部图形度量，男性中扣带回-上顶叶脑区节点效率的右偏不对称性较大，女性中颞极的度中心度的左偏不对称性较大，女性（右偏）和男性（左偏）之间直肠回的度中心度的半球间不对称性的方向相反（均<0.05）。
对于皮质厚度分布与其他脑区的相似性，男性和女性之间扣带回、上顶叶、颞极和直肠回的半球间不对称模式不同。因此，在未来的脑形态和脑结构协变网络研究中，必须考虑性别-半球相互作用的可能影响。
