Cerebellar large-scale network connectivity in Parkinson’s disease: associations with emotion, cognition, and aging effects

Emerging evidence highlights the cerebellum's involvement in Parkinson's disease (PD), yet its intrinsic functional connectivity with cortical-subcortical networks remains largely unexplored. This study aims to investigate cerebellar functional network alterations in PD and their associations with motor, cognitive, and emotional symptoms, as well as age-related effects. 82 participants with PD (PwPD) and 38 healthy controls (HCs) underwent structural and resting-state functional MRI scans. We conducted volumetric analysis in the cerebellum and examined the involvement of cerebellar functional networks in PD, both within-network and between-network connections regarding cortical-subcortical large-scale networks. Additionally, we explored correlations with motor, cognitive, and emotional symptoms, as well as age-related associations in PwPD. No significant differences in cerebellar volume were observed between PwPD and HCs. PwPD exhibited reduced functional connectivity within the cerebellar network and between the cerebellum (CER) and the salience network (SN) (P < 0.001). Decreased CER-SN connectivity correlated with lower MoCA scores and higher HAMD scores, indicating associations with cognitive impairment and depressive symptoms. Additionally, CER-MTL (medial temporal lobe) connectivity positively correlated with both HAMD and HAMA scores in PwPD. Age-related differences in CER-SN connectivity were significant between PwPD and HCs (P = 0.008). Our study suggests the involvement of cerebellar large-scale functional network connectivity in PD, emphasizing the role of cerebellar functional networks in the emotional and cognitive aspects of PD.