Abnormal resting-state cerebellar–cerebral functional connectivity in treatment-resistant depression and treatment sensitive depression

Previous studies have commonly shown that patients with treatment-resistant depression (TRD) and treatment-sensitive depression (TSD) demonstrate a different cerebellar activity. No study has yet explored resting-state cerebellar–cerebral functional connectivity (FC) in these two groups. Here, seed-based FC approach was employed to test the hypothesis that patients with TRD and TSD had a different cerebellar–cerebral FC. The identified FC might be used to differentiate TRD from TSD. Twenty-three patients with TRD, 22 patients with TSD, and 19 healthy subjects (HS) matched with age, gender, and education level participated in the scans. Seed-based connectivity analyses were performed by using cerebellar seeds. Relative to HS, both patient groups showed significantly decreased cerebellar–cerebral FC with the prefrontal cortex (PFC) (superior, middle, and inferior frontal gyrus) and default mode network (DMN) [superior, middle, and inferior temporal gyrus, precuneus (PCu), and inferior parietal lobule (IPL)], and increased FC with visual recognition network (lingual gyrus, middle occipital gyrus, and fusiform) and parahippocampal gyrus. However, the TRD group exhibited a more decreased FC than the TSD group, mainly in connected regions within DMN [PCu, angular gyrus (AG) and IPL]. Further receiver operating characteristic curves (ROC) analyses showed that cerebellar-DMN couplings could be applied as markers to differentiate the two subtypes with relatively high sensitivity and specificity. Both patient groups demonstrate similar pattern of abnormal cerebellar–cerebral FC. Decreased FC between the cerebellum and regions within DMN might be used to separate the two patient groups. ► Little is known about how TRD and TSD differ in cerebellar–cerebral FC ► Patients with TRD are in treatment-resistant state ► Patients with TSD are first-episode, drug-naive, and treatment-sensitive persons ► FC method could detect abnormal cerebellar–cerebral FC between TRD and TSD ► Decreased cerebellar-DMN FC might be used to separate the two patient groups