Resting-State Low-Frequency Cerebellar Oscillations Can Be Abnormal in Parkinson's Disease.

Recent anatomical studies have shown connections between the basal ganglia and the cerebellum. The basal ganglia and cerebellum are major subcortical structures that influence motor and cognitive functions. Recent neuroimaging and animal studies have suggested the role of the cerebellum in the pathophysiology of Parkinson's disease. However, the role of cerebellar oscillations in PD has not been studied. Here, we recruited 75 PD and 39 healthy control subjects to collect cerebellar EEG during a resting-state condition. We followed the recently published protocols to collect cerebellar oscillations. Relative spectral power was computed in the delta, theta, beta, and gamma frequency bands. Further, we performed classifier methods to differentiate PD subjects from controls. We observed significantly increased theta-band (4-7 Hz) relative power in the cerebellar electrodes in PD subjects compared to controls. We also found differences in different frequency bands between mid-cerebellar and nearby mid-occipital EEG signals. Classification analysis using mid-cerebellar theta relative power showed differentiation between PD and control groups. Our results demonstrate that in addition to established cortical and basal ganglia oscillations, abnormal cerebellar oscillations in the theta-band may also participate in the underlying pathophysiology of PD. We suggest that low-frequency cerebellar oscillations may be a potential target for non-invasive neuromodulation to improve PD symptoms.