Role of the cerebellum in the phenotype of neurodegenerative diseases: Mitigate or exacerbate?

Abstract

Degenerative diseases alter brain activity and functional connectivity. In this issue of the Neuroscience Letters, Yin and others (2021) [6] present data showing increased activity in lobules VIII and IX of the cerebellar vermis in Parkinson's patients with visuospatial disorders. The study refines the fMRI mapping of the cerebellum, but the functional interpretation of the findings remains complex. The architecture and connectivity of the cerebellum set it apart from the rest of the brain and should be considered when interpreting the functional connectivity data. In degenerative diseases, the cerebellum suffers from the same pathology as the cerebral cortex; hence, it is unlikely that changes in the cerebellum could ameliorate clinical symptoms in degenerative diseases. Clinical, surgical data indicate that the primary function of the cerebellum is motor, not cognition or affective. The cerebellar anatomy buttresses these observations. The cerebellum receives direct motor-related inputs but no direct information from the sensory system. Hence, it likely contributes to the behavioral components of emotions and cognition.