Creative females have larger white matter structures: Evidence from a large sample study

Abstract

The importance of brain connectivity for creativity has been theoretically suggested and empirically demonstrated. Studies have shown sex differences in creativity measured by divergent thinking (CMDT) as well as sex differences in the structural correlates of CMDT. However, the relationships between regional white matter volume (rWMV) and CMDT and associated sex differences have never been directly investigated. In addition, structural studies have shown poor replicability and inaccuracy of multiple comparisons over the whole brain. To address these issues, we used the data from a large sample of healthy young adults (776 males and 560 females; mean age: 20.8 years, SD = 0.8). We investigated the relationship between CMDT and WMV using the newest version of voxel-based morphometry (VBM). We corrected for multiple comparisons over whole brain using the permutation-based method, which is known to be quite accurate and robust. Significant positive correlations between rWMV and CMDT scores were observed in widespread areas below the neocortex specifically in females. These associations with CMDT were not observed in analyses of fractional anisotropy using diffusion tensor imaging. Using rigorous methods, our findings further supported the importance of brain connectivity for creativity as well as its female-specific association. Hum Brain Mapp 38:414-430, 2017. © 2016 Wiley Periodicals, Inc.

Keywords: creativity; sex difference; structural connectivity; voxel-based morphometry; white matter.

Figure 1

Effects of interaction between CMDT and sex on rWMV. The two left columns show the areas of significant interaction effects of CMDT and sex on rWMV. The two right columns show the areas of significant positive correlation between CMDT and rWMV. The results shown were obtained using a threshold of TFCE, P < 0.05 corrected (FWE) based on 5,000 permutations. Regions of correlation are overlaid on a single subject T1 image of SPM. Significant sex‐related interaction effects that are moderated by female‐specific positive correlation between CMDT and rWMV are seen in widespread areas below the cortex.

Figure 2

Significant main effects of S‐A creativity test total score and subscale scores on rWMV. The figures in the left columns show the areas with significant main effects of total score and each S‐A creativity test subscale score on rWMV. The results shown were obtained using a threshold of TFCE, P < 0.05 corrected (FWE) based on 5,000 permutations. Regions of correlation are superimposed on a glass brain image of SPM. There were significant main effects of originality subscore on rWMV in the area adjacent to the right inferior parietal lobule and right post central gyrus. The figures in the right columns show the areas of tendencies for main effects of S‐A creativity test total score and each subscale score on rWMV. The results shown were obtained using a threshold of TFCE, P < 0.05 uncorrected based on 5,000 permutations. Regions of correlation are superimposed on a glass brain image of SPM. There were tendencies for effects of originality subscore on rWMV in widespread areas.

Figure 3

Effects of interactions between S‐A creativity test scores (total score and each subscale score) and sex on rWMV moderated by negative correlations in males and positive correlations in females. The figures in the left columns show the areas of significant interaction effects of S‐A creativity test total score and subscale scores on rWMV. The results shown were obtained using a threshold of TFCE, P < 0.05 corrected (FWE) based on 5,000 permutations. Regions of correlation are superimposed on a glass brain image of SPM. There were significant interaction effects of total score and sex on rWMV in widespread areas and significant interaction effects of elaboration subscore and sex on rWMV in widespread areas. Significant interaction effects of fluency subscore and sex on rWMV were more confined, but found in several distributed areas. The figures in the right columns show the areas of tendencies for interaction effects between S‐A creativity test scores (total score of each subscale score) and sex on rWMV moderated by negative correlations in males and positive correlations in females. The results shown were obtained using a threshold of TFCE, P < 0.05 uncorrected based on 5,000 permutations. Regions of correlation are superimposed on a glass brain image of SPM. There were tendencies for effects of each score on rWMV in widespread areas.