Functional Magnetic Resonance Imaging-Specific Alternations in the 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 a dysfunctional default mode network (DMN) plays a key role in the pathophysiological mechanisms of OCD. However, findings of impaired DMN regions in OCD have been inconsistent. We used meta-analysis to identify functional magnetic resonance imaging (fMRI)-specific abnormalities of the DMN in OCD.

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

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

Conclusions: Patients with OCD showed dysfunction in the DMN, including impaired local important nodal brain regions. The parietal cingulate cortex/precuneus appeared to be the most affected regions within the DMN, providing valuable insights into understanding the potential pathophysiology of OCD and targets for clinical interventions.