Decreased regional homogeneity in major depression as revealed by resting-state functional magnetic resonance imaging

Backgroud Functional imaging studies indicate abnormal activities in cortico-limbic network in depression during either task or resting state. The present work was to explore the abnormal spontaneous activity shown with regional homogeneity (Re Ho) in depression by resting-state functional magnetic resonance imaging (fMRI). Methods Using fMRI, the differences of regional brain activity were measured in resting state in depressed vs. healthy participants. Sixteen participants firstly diagnosed with major depressive disorder and 16 controls were scanned during resting state. A novel method based on Re Ho was used to detect spontaneous hemodynamic responses across the whole brain. Results Re Ho in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe was found to be significantly decreased in depression compared to healthy controls in resting state of depression. Conclusions Abnormal spontaneous activity exists in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe. And the Re Ho may be a potential reference in understanding the distinct brain activity in resting state of depression. Chin Med J 2011;124(3):369-373