Increased resting-state functional connectivity between the anterior cingulate cortex and the precuneus in panic disorder: resting-state connectivity in panic disorder.

BACKGROUND: The structural and functional abnormalities of the anterior cingulate cortex (ACC) have been reported in panic disorder (PD). Patients with PD have shown decreased gamma-aminobutyric acid (GABA) concentration in the ACC. The GABA concentration in the ACC was found to be associated with default mode network (DMN) activity in normal human subjects. Therefore, it was hypothesized that the DMN would show abnormal activity in PD.

METHODS: We identified and compared the functional connectivity maps with seed region of interest (ROI) located in the perigenual area of ACC between the 11 patients with panic disorder and age- and sex-matched normal control subjects. Combining magnetic resonance spectroscopy (MRS) and resting fMRI, we investigated the correlation between the GABA concentration in the seed ROI and the index of functional connectivity between ACC and the area showing group differences.

RESULTS: The patients with PD showed increased functional connectivity between ACC and precuneus compared to control subjects. The functional connectivity between the ACC and the precuneus negatively correlated with the GABA concentration of the ACC.

LIMITATIONS: The relatively small sample size and seed based analysis with the selection of a single ROI limits the generalizability of the result.

CONCLUSIONS: Increased functional connectivity in the two medial nodes of the resting-state default mode network, the ACC and the precuneus, might play an important role in the pathophysiology of panic disorder. The treatment aimed to normalize the functional connectivity between ACC and precuneus might have clinical benefits in PD.