Correlation Between Resting Brain Function Alterations And Resilience At High-risk Individuals In Bipolar Disorder

Objective: Using resting-state functional magnetic resonance imaging(rs-fMRI),we examed the gray matter structure and the regional brain activity at rest in the high-risk(HR)stages of bipolar disorder to investigate risk-related mechanisms of the disorder.We further explored the correlation between structural and functional changes and resilience in HR group for providing neuroimaging evidence of the neural basis of resilience alterations.Methods: A total of 44 healthy first-degree relatives of bipolar disorder(HR)and 51 healthy controls(HCs)matched with gender and age were enrolled to complete structural and functional MRI scans,and the Connor-Davidson resilience scale(CDRISC).Voxel-based morphology(VBM),the amplitude of low-frequency fluctuation(ALFF)and the regional homogeneity(ReHo)methods were used to analyze alterations of brain structure and function.Independent sample t test was used to compare the parameters between the two groups;then the CD-RISC scale was used for selfassessment,and the total score and the factor 1 to factor 5(F1-F5)scores of the two groups were analyzed by independent sample t test.Partial correlation analysis was conducted between the results of VBM,ALFF and ReHo analysis and the CD-RISC score.Results: In terms of brain structure characteristics,no significant differences in gray matter volume was found between the two groups.In terms of brain function characteristics,HR group showed decreased ALFF in the left precuneus(t=-3.52),and decreased ReHo in bilateral lingual gyrus/cerebellar vermis(t=-3.44)compared with HC group(all P<0.05,GRF corrected).In terms of resilience characteristics,HR group showed significantly lower F3(the positive acceptance of change,and secure relationships)level compared with HC group(P<0.05).Positive correlation was found between the ALFF of the left precuneus and the F3 score(r=-0.459,P=0.014)in HR group.Conclusion: Changes of brain structure of the HR group was not found.Decreased regional activities of the precuneus and lingual gyrus/cerebellar vermis suggesting alterations of brain function arose earlier than brain structure,which underline a potential neuropathological mechanism for the risk of bipolar disorder.And brain functional changes may be earlier than structural changes.Abnormal brain activity in the precuneus was positively associated with reduced resilience in the HR group,indicating motion regulation dysfunction in HR group was associated with the decreased activity in the precuneus.