LAUSR

PURPOSE Visuospatial disorders (VSDs) are common in Parkinson's disease (PD). VSDs may involve cerebellar vermis, but evidence from functional connectivity (FC) studies is lacking. Here we compared FC between cerebellar vermis and the entire brain between PD patients with or without VSD, and between patients and healthy controls. METHODS Resting-state 3.0-T functional magnetic resonance imaging was performed on 19 controls, 31 PD patients with VSD and 12 PD patients without VSD. Correlations in brain network were calculated between eight regions of interest in the cerebellar vermis (I-VIII) and other voxels in the brain, and voxel-based FC was analyzed. Patients were assessed in terms of cognitive function as well as motor and non-motor symptoms. RESULTS In both types of patients, cerebellar vermis VIII, IX and X showed positive FC with the default-mode network (DMN), executive control network and sensorimotor network. Cerebellar vermis I and II showed positive FC with the visual network and DMN in controls, but negative FC in PD patients without VSD. Cerebellar vermis X showed negative FC with lobules VIII and IX of the left cerebellar hemisphere in controls, but positive FC in PD patients with VSD. CONCLUSION Positive FC connecting the cerebellar vermis VIII and X with associated brain networks in PD patients with VSD may be compensatory activation. PD may involve disruption of functional coupling between the cerebellar vermis and cerebral cortex.