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Gender differences in the relationship between gray matter structure and psychological resilience in late adolescence1Huaxi MR Research Center, West China Hospital, Sichuan University, Chengdu, China
Synopsis
Although behavioral studies have shown that males are more resilient than females, the effects of gender on the relationship between brain structure and psychological resilience are largely unknown. Here, we investigated the gender-specific associations between psychological resilience and regional gray matter volume (GMV) in 231 healthy adolescents via structural magnetic resonance imaging. We found that the relationship between psychological resilience and GMV differed between genders in the left ventrolateral prefrontal cortex, with a positive correlation in males and a negative correlation in females. Therefore, our study provided the first evidence for the gender-specific neuroanatomical correlates of psychological resilience.
Introduction
Psychological resilience reflects an individual ability to adapt well and cope successfully in the face of adversity1, which is associated with positive physical and mental outcomes2,3. Gender differences in psychological resilience have always been of great interest to researchers and convergent evidence has shown that males were more resilient than females3-5. However, little is known about the gender-specific neuroanatomical substrates involved in psychological resilience. Thus in this study, we aimed to explore the gender differences in the association between psychological resilience and brain structure in a large sample of healthy adolescents by using a voxel-based morphometry (VBM) approach measured with structural magnetic resonance imaging (sMRI).Methods
Two hundred and thirty-four healthy students (122 females; mean age= 18.60 years, SD= 0.78) from several public high schools were included. Three participants were removed due to unusual brain structure. Therefore, 231 participants (121 females; mean age = 18.48 years, SD= 0.54) were included in the data analysis. Psychological resilience of each subject was assessed using Chinese version of Connor–Davidson Resilience Scale (CD-RISC)6, 7. Moreover, to rule out the possible effect of general intelligence and ‘big five’ personality traits on the association between brain structure and psychological resilience, the data on the Raven’s Advanced Progressive Matrix (RAPM) and NEO Five-Factor Inventory (NEO-FFI) were collected. The imaging data were collected using a Siemens-Trio Erlangen MRI scanner equipped with a 12-channel head coil. T1-weighted anatomical images of each subject were obtained using the following scanning parameters: voxel size, 1 × 1 × 1 mm3; flip angle, 9°; matrix size, 256 × 256; slice thickness, 1 mm; 176 slices; echo time, 2.26 ms; inversion time, 900 ms; repetition time, 1900 ms. The imaging data preprocessing was conducted using the Statistical Parametric Mapping program (SPM8) with the major steps as follows, registration, normalization and smoothness. We used a voxel-wise condition-by-covariate interaction analysis8 in SPM8 to detect the gender-specific relationship between regional gray matter volume (GMV) and psychological resilience. Gender was treated as a condition, and age, total GMV, RAPM and NEO-FFI were treated as covariates. T-contrasts were used to assess the interaction effect of gender and psychological resilience on regional GMV. For multiple comparisons correction, we used the nonstationary cluster correction approach9, with a threshold of p < 0.05 at the cluster level and p < 0.0025 at the voxel level. Then for regions where a significant correlation in each gender was found, we investigated whether a significant difference in the relationship could be found between the two genders using Fisher’s z test10.Results
At the behavioral level, we found that males scored significantly higher than females on psychological resilience (t229 = 3.609, p < 0.001, Cohen’d = 0.475), which is consistent with previous findings3-5. At the neural level, we detected significant gender differences in the relationships between psychological resilience and the GMV in the left ventrolateral prefrontal cortex (VLPFC; MNI coordinates: -40, 24, -14; cluster size= 499 voxels; T= 4.00; p < 0.0025; Figure 1), after controlling for age, total GMV, RAPM and NEO-FFI dimensions. Interestingly, higher psychological resilience was associated with larger left VLPFC volume in the males (r= 0.324, p < 0.001), whereas females showed a negative correlation (r= -0.247, p < 0.001). Fisher’ z test indicated a significant gender difference (Z = 4.407, p < 0.05) in the correlation between psychological resilience and the regional GMV in the left VLPFC.Discussion
The present study revealed the gender-specific neural correlates of psychological resilience. Behaviorally, we found that males were more resilient than females, which fits well with previous findings3-5. Neurally, a significant positive correlation between psychological resilience and the GMV in the left VLPFC was observed among males, while a negative correlation was found among females in this region. The VLPFC is importantly involved in emotion processing and regulation11, which are constructs closely related to psychological resilience12. Moreover, many structural studies of stress-related mental disorders have reported that the VLPFV might play an important role in the brain mechanism of these disorders and represent a risk factor for the disorders13-15. In addition, the brain development in adolescence differs between genders and it’s reported that the prefrontal cortex undergoes gray matter volume reduction earlier in females than in males16. Moreover, the gender differences detected in the correlation between psychological resilience and GMV might be attributed to the different sex hormonal levels, genetic and environmental factors between males and females16.Conclusion
Taken together, our study provided the first evidence in healthy adolescents that the VLPFC might be a key region in the gender-specific relationships between psychological resilience and brain structure.Acknowledgements
No acknowledgements.References
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