Functional MRI-Specific Alternations in default mode network in obsessive-compulsive disorder: A voxel-based meta-analysis.

Background: Obsessive-compulsive disorder (OCD) is a common and debilitating mental disorder. Neuroimaging studies have highlighted that the dysfunctional default mode network (DMN) plays a key role in the pathophysiology mechanisms of OCD. However, the findings of impaired DMN regions have been inconsistent. We employed meta-analysis to identify the fMRI-specific abnormalities of the DMN in OCD.

Methods: PubMed, Web of science and Embase were searched to screen resting-state functional magnetic resonance imaging (rs-fMRI) studies on the amplitude of low-frequency fluctuation/fractional amplitude of low-frequency fluctuation (ALFF/fALFF) and regional homogeneity (ReHo) of the DMN in OCD patients. Based on the activation likelihood estimation (ALE) algorithm, we compared all patients with OCD and control group in a primary meta-analysis, and analyzed the unmedicated OCD without comorbidities in secondary meta-analyses.

Results: A total of 26 eligible studies with 1219 OCD patients (707men) and 1238 healthy controls (684 men) were included in the primary meta-analysis. We concluded specific changes in brain regions of DMN, mainly in the left medial frontal gurus (MFG), bilateral superior temporal gyrus (STG), bilateral inferior parietal lobule (IPL), bilateral precuneus (PCUN), bilateral posterior cingulate cortex (PCC), and right parahippocampal gyrus (PHG).

Conclusion: OCD patients showed dysfunction in the DMN, including impaired local important nodal brain regions. The PCC/PCUN appear to be the most affected regions within the DMN, providing valuable insights into understanding the potential pathophysiology of OCD and targets for clinical interventions.