Characterization of resting-state fMRI-derived functional connectivity in patients with deficiency versus excess patterns of major depression.

OBJECTIVE

Patients with major depression (MD) experience a variety of emotional and mental problems accompanied by characteristic clinical symptoms. Based on traditional Chinese medicine (TCM) notions, the clinical appearance of MD can be divided into two syndromes, namely a deficiency pattern (DP) and an excess pattern (EP), depending on the patient's clinical symptoms, pulse, and lingual signs. Brain functional neuroimaging has demonstrated cerebral activity abnormalities in MD patients. However, such abnormalities have not been linked to particular symptoms of MD. The objective of this work was to compare functional connectivity of the posterior cingulate cortex (PCC) across MD patients with DP, MD patients with EP, and normal control (NC) subjects in a resting-state functional magnetic resonance imaging (rs-fMRI) study.

METHODS

Participants (24 DP patients, 21 EP patients, and 20 NCs) underwent rs-fMRI scans. Whole-brain functional connectivity of a seed in the PCC was then mapped for each subject. Functional connectivity differences among the three studied groups were analyzed statistically.

RESULTS

Compared to the NC group, DP patients had decreased functional connectivity of the PCC with the right middle temporal gyrus and bilateral precuneus, as well as increased functional connectivity of the PCC with the bilateral middle frontal gyrus. Meanwhile, compared to the NC group, the EP group had decreased functional connectivity of the PCC with both the middle temporal gyrus and bilateral precuneus, as well as increased functional connectivity of the PCC with the bilateral superior frontal gyrus. Relative to the DP group, the EP group had reduced functional connectivity of the PCC with the bilateral cerebellum and left superior frontal gyrus.

CONCLUSION

Functional connectivity changes differ between MD patients with different TCM syndrome types, suggesting that the TCM clinical syndromes of MD are associated with correlates in cerebral functional activity.