Dissociation Pattern in Default-Mode Network Homogeneity in Drug-Naive Bipolar Disorder

Abstract

Default mode network (DMN) plays a key role in the pathophysiology of in bipolar disorder (BD). However, the homogeneity of this network in BD is still poorly understood. This study aimed to investigate abnormalities in the NH of the DMN at rest and the correlation between the NH of DMN and clinical variables in patients with BD. Forty drug-naive patients with BD and thirty-seven healthy control subjects participated in the study. Network homogeneity (NH) and independent component analysis (ICA) methods were used for data analysis. Support vector machines (SVM) method was used to analyze NH in different brain regions. Compared with healthy controls, significantly increased NH in the left superior medial prefrontal cortex (MPFC) and decreased NH in the right posterior cingulate cortex (PCC) and bilateral precuneus were found in patients with BD. NH in the right PCC was positively correlated with the verbal fluency test and verbal function total scores. NH in the left superior MPFC was negatively correlated with triglyceride (TG). NH in the right PCC was positively correlated with TG but negatively correlated with high-density lipoprotein cholesterol (HDL-C). NH in the bilateral precuneus was positively correlated with cholesterol and low-density lipoprotein cholesterol (LDL-C). In addition, NH in the left superior MPFC showed high sensitivity (80.00%), specificity (71.43%), and accuracy (75.61%) in the SVM results. These findings contribute new evidence of the participation of the altered NH of the DMN in the pathophysiology of BD.

Potential correlations between abnormal homogeneity of default mode network and personality or lipid level in major depressive disorder

“…Subsequently, they could induce overactivation of the hypothalamus–pituitary–adrenal axis, resulting in heightened hormone levels in the central nervous system and the attenuation of negative feedback regulation. This, in turn, may lead to metabolic issues such as elevated blood sugar (Li, Teng et al., 2021 ). It is plausible that, among patients with MDD, the impact of depressive symptoms may contribute to a diminished appetite and reduced food intake, culminating in decreased lipid levels.…”

“…Network homogeneity (NH), a method proposed by Uddin et al primarily investigates functional connectivity between specific voxels within a particular network such as the DMN (Li, Teng et al, 2021).…”