Beta Oscillatory Activity in the Subthalamic Nucleus and Its Relation to Dopaminergic Response in Parkinson's Disease

TLDR

Beta oscillatory activity (15–30 Hz) in the subthalamic nucleus is markedly increased in Parkinson’s disease, interferes with movement, and is reduced by dopaminergic medication or deep‑brain stimulation, yet its prevalence and relationship to neuronal activity remain unclear. The study aimed to record simultaneous local field potential and neuronal spike activity from the STN in 14 Parkinson’s disease patients during functional neurosurgery. Recordings were obtained intraoperatively, capturing both LFPs and single‑ and multi‑unit spikes from the STN. Of 200 recorded units, 56 showed ~26 Hz oscillations, 89 % of which were coherent with LFP, with a higher incidence in the dorsal STN that correlated positively with dopaminergic medication benefit but not with baseline motor deficits, indicating that neuronal beta activity reflects the basal ganglia’s response to dopaminergic agents and is largely generated in the dorsal STN, producing synchronous oscillations in local neurons.

Abstract

Recent studies suggest that beta (15-30 Hz) oscillatory activity in the subthalamic nucleus (STN) is dramatically increased in Parkinson's disease (PD) and may interfere with movement execution. Dopaminergic medications decrease beta activity and deep brain stimulation (DBS) in the STN may alleviate PD symptoms by disrupting this oscillatory activity. Depth recordings from PD patients have demonstrated beta oscillatory neuronal and local field potential (LFP) activity in STN, although its prevalence and relationship to neuronal activity are unclear. In this study, we recorded both LFP and neuronal spike activity from the STN in 14 PD patients during functional neurosurgery. Of 200 single- and multiunit recordings 56 showed significant oscillatory activity at about 26 Hz and 89% of these were coherent with the simultaneously recorded LFP. The incidence of neuronal beta oscillatory activity was significantly higher in the dorsal STN (P = 0.01) and corresponds to the significantly increased LFP beta power recorded in the same region. Of particular interest was a significant positive correlation between the incidence of oscillatory neurons and the patient's benefit from dopaminergic medications, but not with baseline motor deficits off medication. These findings suggest that the degree of neuronal beta oscillatory activity is related to the magnitude of the response of the basal ganglia to dopaminergic agents rather than directly to the motor symptoms of PD. The study also suggests that LFP beta oscillatory activity is generated largely within the dorsal portion of the STN and can produce synchronous oscillatory activity of the local neuronal population.