Different characteristics of striatal resting-state functional conectivity in treatment-resistant and non-treatment-resistant depression.

Major depressive disorder is associated with a reward deficit manifested by abnormal striatal function. However, differences between treatment-resistant depression (TRD) and non TRD (nTRD) in striatal whole-brain functional connectivity (FC) have not been elucidated. Thirty-eight patients with TRD, 42 patients with nTRD, and 39 healthy controls (HCs) were recruited for this study. A seed-based FC approach was used to analyze abnormalities in six predefined striatal subregion circuits in the three groups of subjects, and further explore the correlation between abnormal FC and clinical symptoms. Results revealed that compared with the nTRD group, the TRD group showed increased FC of the inferior ventral striatum with the bilateral orbital area of the middle frontal gyrus, right cerebellum posterior lobe, left parahippocampal gyrus, left middle occipital gyrus and left lingual gyrus. Compared with the HC group, the TRD group showed a wider range of altered striatal function than the nTRD group. In the TRD group, the HAMD-17 scores were positively correlated with the FC between the right VRP and the left caudate. This study provides new insights into understanding the specificity of TRD striatal circuits.