Advancements in the study of large-scale network alterations in brain functional connectivity among individuals with bipolar disorder.

Abstract

Background: Bipolar disorder (BD) is characterized by structural and functional impairments of varying severity. However, inconsistent findings from previous studies have led to an incomplete understanding of the precise associations both within and between functional networks in BD. Analysis from a large-scale network perspective may offer more comprehensive insights.

Method: Studies that used functional magnetic resonance imaging (fMRI) to explore the changes in functional connectivity (FC) within and between major brain networks in patients with BD were included by searching for keywords such as "bipolar disorder," "brain networks," and "functional connectivity" in PubMed and Web of Science.

Result: 51 studies met the inclusion criteria. At rest, BD patients exhibited reduced intrinsic connectivity within the default mode network (DMN), salience network (SAN), and central executive network (CEN). Furthermore, alterations were observed in other networks, suggesting a complex pattern of connectivity changes associated with emotional states and cognitive functions.

Conclusion: BD disrupts the activity of brain networks during both resting state and task stimulation. Posterior cingulate cortex (PCC), anterior insula (AI), postcentral gyrus (PoCG), and precuneus (PreCu) play a crucial role in the identification and diagnosis of BD. They are significant in differentiating BD from other mental illnesses and assessing patients' cognitive deficits. However, this study has limitations in the insufficient exploration of other potentially related networks.