Altered Functional Connectivity of Ventral Striatum Subregions in De-novo Parkinson's Disease with Depression.

Although various studies have reported a high prevalence of depression among Parkinson's disease (PD) patients, the pathophysiological mechanism of depression in PD (DPD) is still unclear. The core region of the reward network, the ventral striatum (VS), is critical in the occurrence and development of DPD. This study aimed to explore the altered functional connectivity (FC) of VS subregions in DPD. We recruited 20 DPD patients, 37 non-depressed PD (NDPD) patients, and 41 healthy controls (HC) matched in age, gender, and years of education. The patients' diagnosis with PD was de-novo. We then used resting-state functional magnetic resonance imaging to detect the FC differences of VS subregions among these groups. The FC between the left ventral caudate (vCa_L) and the left middle occipital gyrus (MOG.L) was significantly increased in DPD than in NDPD patients or HC. Compared with HC, NDPD patients exhibited significantly increased FCs between bilateral ventromedial putamen and the left paracentral lobule, the right ventromedial putamen (vmPu_R), and the right precentral gyrus, the vmPu_R, and the left precuneus. Besides, a significant negative correlation was found between the FC values of the vCa_L with the MOG.L and the HAMD-17 scores in the DPD group. The hyperconnectivity between vCa_L and the MOG.L might be viewed as a compensatory mechanism for depression in the early stage of PD. This study provides new insight into the neural mechanism of depression in the early stage of PD and contributes to explore the potential neuroimaging markers for DPD.