Approved research

Altered connectivity between the two brain hemispheres in the depressive personality

Lay summary

Altered connectivity between the two brain hemispheres has been found in mental disorders. Previous study of our group has shown decreased between-hemispheres connectivity in patients with late-life depression relative healthy controls. However, systematic study is still lacking regarding which factors are related to the between-hemisphere connectivity reduction: cerebrovascular disorders, clinical symptoms, gender, personality traits, genetic factors or some key life-style factors. In this study, we propose to combine brain structural and functional MRI data with other non-imaging data such as depression-related genetic variants, personality traits, mood and anxiety as well as other clinical symptoms, cognitive function, life-styles, gender, blood pressure, and gait speed etc to examine which of these factors is highly associated with reduced between-hemisphere connectivity in major depression. Given the vital role of corpus callosum in connecting the two hemispheres, we will further subdivide the corpus callosum into small circles with 5mm in diameter and 5 mm apart between any two sub-regions. Between-hemisphere connectivity is a key neural connectivity feature vital for many behaviors, yet has been relatively neglected. Our project will not only identify factors related to the reduction of between-hemisphere connectivity, but also can determine the related gene loci regulating the connection between the hemispheres in healthy controls but genetic variants that contribute to the reduction of between-hemisphere connectivity and depression. The moderation/modulation effects among these factors will also be examined.