Subthalamic Movement Related Beta Oscillatory Activity During Voluntory Movement In Patients With Parkinson’s Disease

Objective : To explore voluntary movement related neuronal activity in the subthalamic nucleus in patients with Parkinson’s disease(PD).Methods:17 PD patients(M:7; F:10) who underwent STN deep brain stimulation(DBS) for parkinsonian symptoms were studied.Their mean age was 58.5±5.4 years old and mean disease duration was 6.9±3.6 years. Microelectrode recordings in the STN and EMG recordings on the contralateral limbs to surgery were simultaneously performed.Patients performed at least 10 self-paced wrist extension movements at 10 sec intervals during the recordings. All patients were trained to perform the task before surgery. Single-unit analysis with mean neuronal firing rate(MFR) and coefficient of variation(CV) of inter-spike interval(ISI) were calculated.Power spectral analysis was used to evaluate neuronal oscillation patterns.Based on the movement onset, four periods were determined: baseline(2 s), pre-movement(3 s), movement execution and post-movement(2 s). ANOVA and Bonferroni test were performed to compare the change of MRF and CV of neurons among four periods of movement.Results:119 neurons were identified from 21 STN.Of these neurons,38.7% were neurons(n=46) with β oscillation at range of 13~30 Hz(mean 21.0 ± 5.1 Hz). Of these ? oscillatory neurons, 43.5%(n=20) were related wrist movement. 26.1%(n=12) were desynchronized, showing reduced firing rate, and 17.4%(n=8) were synchronized, showing increased firing rate. Bonferroni test showed that there were significant changes of mean firing rate between baseline and movement execution in neurons desynchronized(37.5±7.6 Hz vs 20.4±5.2 Hz) or synchronized(39.7±7.3 Hz vs 53.9±9.5 Hz) during movement. Furthermore, these movement related neurons were localized in the dorsal portion of the STN.Conclusions: The data support the view that the STN ? oscillatory neurons are modulated with the execution of self-paced movement. The desynchronization or synchronization of the STN ? oscillatory activity might play a role in generation movement. Moreover, the localizations of the movement related ? oscillatory neurons is within the dorsal portion of the STN, adding to the evidence that this is the motor part of the STN. The region leads to an effective clinical outcome for STN DBS surgery.