Striato‐cortical connections in Parkinson's and Alzheimer's diseases: Relation to cognition

Abstract

BACKGROUND: Functional connectivity is abnormal in PD and in early Alzheimer's disease. OBJECTIVES: The objective of this study was to evaluate resting-state striato-cortical connectivity in PD and Alzheimer's disease and assess their relation to cognitive outcomes. Groups with mild cognitive impairment as a result of different pathologies (PD vs. Alzheimer's disease) were also compared. METHODS: Seed-based connectivity of the dorsal, middle, and ventral striatum was analyzed in 111 patients using functional MRI. The correlation between connectivity at regions of between-group differences and clinical outcomes was assessed. RESULTS: Patients showed lower striatal connectivity than controls. Connectivity between the middle (associative) striatum and precuneus negatively correlated with executive functions in PD and with memory performance in Alzheimer's disease. PD with cognitive impairment showed decreased connectivity of the dorsal (motor) striatum when compared with early Alzheimer's disease. CONCLUSIONS: Striatal connectivity was reduced in patients when compared with controls. Similar compensatory mechanisms were employed to overcome various cognitive deficits in PD and Alzheimer's disease. © 2017 International Parkinson and Movement Disorder Society.