Oscillatory activity in the globus pallidus internus: Comparison between Parkinson’s disease and dystonia

ObjectiveDeep brain stimulation in the globus pallidus internus (GPi) is used to alleviate the motor symptoms of both Parkinson’s disease (PD) and dystonia. We tested the hypothesis that PD and dystonia are characterized by different temporal patterns of synchronized oscillations in the GPi, and that the dopaminergic loss in PD makes the basal ganglia more susceptible to oscillatory activity.MethodsNeuronal firing and local field potentials (LFPs) were simultaneously recorded from the GPi in four PD patients and seven dystonia patients using two independently driven microelectrodes.ResultsIn the PD patients, beta (11–30 Hz) oscillations were observed in the LFPs and the firing activity of ∼30% of the neurons was significantly coherent with the LFP. However, in the dystonia group, the peak frequency of LFP oscillations was lower (8–20 Hz) and there was a significantly smaller proportion of neurons (∼10%) firing in coherence with the LFP (P < 0.001).ConclusionsThese findings suggest that synchronization of neuronal firing with LFP oscillations is a more prominent feature in PD than in dystonia.SignificanceThis study adds to the growing evidence that dopaminergic loss in PD may increase the sensitivity of the basal ganglia network to rhythmic oscillatory inputs.

► 30% of globus pallidus neurons in Parkinson’s disease patients have 11–30 Hz beta oscillatory activity.
► Globus pallidus firing is coherent with the local field potential (LFP) oscillatory activity in the beta range.
► In dystonia patients LFP and neuronal oscillatory activity frequency is 8–10 Hz and only 10% of neurons fire coherently.