Investigating spontaneous brain activity in bipolar disorder: A resting-state functional magnetic resonance imaging study

BACKGROUND: Despite several neuroimaging studies in the past few years, the exact pathophysiology responsible for the development of bipolar disorder (BD) is still not completely known. Importantly, to the best of our knowledge, no study from India has examined resting state (RS) connectivity abnormalities in BD using regional homogeneity (ReHo). Hence, we examined spontaneous brain activity in patients with BD using RS functional magnetic resonance imaging (RS-fMRI). AIM: The aim of the study is to examine the spontaneous brain activity in patients with BD-I using ReHo approach and RS-fMRI compared to age- and gender-matched healthy control (HC). MATERIALS AND METHODS: A total of 20 patients with BD and 20 age-, gender-, and education-matched HCs participated in the study. The fMRI data were obtained using 1.5T scanner. RS-fMRI abnormalities were analyzed using ReHo method. RESULTS: Compared to healthy adults, significantly increased ReHo in the BD group was found in the right precuneus, right insula, right supramarginal gyrus, left superior frontal gyrus, right inferior frontal gyrus, right precentral gyrus, and right paracentral lobule. No region had significantly lower ReHo values in BD patients compared to controls. CONCLUSION: These results suggested that abnormal local synchronization of spontaneous brain activity is present in the frontoparietoinsular region which may be related to the pathophysiology of BD.