High‐frequency oscillations in Parkinson's disease: Spatial distribution and clinical relevance

Abstract

The pathophysiology of Parkinson's disease (PD) has been related to excessive beta band oscillations in the basal ganglia. Recent recordings from the subthalamic nucleus of PD patients showed that beta oscillations show strong cross-frequency coupling with high-frequency oscillations (>200 Hz). However, little is known about the characteristics and functional properties of these oscillations. We studied the spatial distribution of high-frequency oscillations and their relation to PD motor symptoms. We included 10 PD patients in medication OFF who underwent implantation of deep brain stimulation (DBS) electrodes. Intraoperative five-channel microelectrode recordings were performed at 9 to 10 recording sites within the subthalamic nucleus and its immediate surroundings. We found a focal spatial distribution of high-frequency oscillations with highest power 2 mm below the dorsolateral border of the subthalamic nucleus. Within the subthalamic nucleus, power peaked slightly anterior to the DBS target site. In addition, contralateral akinesia/rigidity scores were negatively correlated with high-frequency oscillation power. Our results demonstrate a focal origin of high-frequency oscillations within the subthalamic nucleus and provide further evidence for their functional association with motor state.

Suppression of spontaneous oscillations in high-frequency stimulated neuron models

“…The HFO power increases when movements are initiated and decreases when the latter end [51,54]. Accordingly, HFO power is negatively correlated with the akinesia/rigidity of the corresponding (contralateral) side [55].…”

Parkinsonian Rest Tremor Is Associated With Modulations of Subthalamic High‐Frequency Oscillations

“…HFOs have been observed both intra‐ and postoperatively in the STN of PD and non‐PD patients, and beta‐HFO PAC has been observed in the pallidum of dystonia patients and healthy macaques . Thus, HFOs do not seem to be a sign of any specific disease, but they may undergo specific alterations in the course of a disease.…”

“…High‐frequency oscillations (HFOs; >200 Hz) have been observed in the subthalamic nucleus (STN) and globus pallidus internus . Similar to the beta‐gamma coupling observed in motor cortex, the amplitude of subthalamic HFOs is coupled to the phase of beta oscillations (13‐30 Hz).…”

“…For each STN contralateral to the tremulous limb, the contact with the highest HFO peak at rest was selected (pooled epochs from REST‐TREMOR and REST‐NOTREMOR). This choice was motivated by the observation that the spatial distribution of HFO power peaks within the STN . Peaks were found by searching the derivative for zero crossings and applying a peak width threshold of 10 Hz .…”

“…This choice was motivated by the observation that the spatial distribution of HFO power peaks within the STN . Peaks were found by searching the derivative for zero crossings and applying a peak width threshold of 10 Hz . Peak frequencies and peak heights for selected contacts are given in Table .…”