Gender consistency and difference in healthy adults revealed by cortical thickness

Many previous studies have shown that there exists the gender effect on the structural and functional organization in the human brain. Although the reported functional differences are generally consistent, the structural differences are controversial among the various studies. In this study, we particularly focused on the gender-related effect in the gray matter (GM). We performed a structural magnetic resonance imaging (MRI) study in 184 healthy adults (90 males and 94 females) with ages ranging from 18 to 70 years. Cortical thickness was measured using an automated surface-based method. Based on this surface morphological feature of GM, we first compared their regional differences between males and females. We then constructed the morphometry-based anatomical networks derived from cortical thickness measurement, while the anatomical connection between two cortical areas depended upon the statistical dependence of their cortical thickness across subjects. Subsequently, we applied graph theoretical approaches to investigate the properties of the resultant anatomical networks. The results showed that the significant gender-related differences of cortical thickness appeared extensively in the frontal, parietal and occipital lobes. And there were also some between-group differences in the interregional correlation. Additional graph theoretical analysis on the morphological networks revealed both networks exhibited the small-world efficiency and their patterns of topological vulnerability had no statistical differences. The findings on the large sample may provide the evidences to study the gender consistency and difference in the human brain structures.