Objectives

To evaluate the correlation between the pallidal local field potentials (LFPs) activity and the cortical oscillations (at rest and during several motor tasks) in two freely moving patients with generalized dystonia and pallidal deep brain stimulation (DBS).

Materials and Methods

Two women with isolated generalized dystonia were selected for bilateral globus pallidus internus (GPi) DBS. After the electrodes' implantation, cortical activity was recorded by a portable electroencephalography (EEG) system simultaneously with GPi LFPs activity, during several motor tasks, gait, and rest condition. Recordings were not performed during stimulation. EEG and LFPs signals relative to each specific movement were coupled together and grouped in neck/upper limbs movements and gait. Power spectral density (PSD), EEG-LFP coherence (through envelope of imaginary coherence operator), and 1/f exponent of LFP-PSD background were calculated.

Results

In both patients, the pallidal LFPs PSD at rest was characterized by prominent 4–12 Hz activity. Voluntary movements increased activity in the theta (θ) band (4–7 Hz) compared to rest, in both LFPs and EEG signals. Gait induced a drastic raise of θ activity in both patients' pallidal activity, less marked for the EEG signal. A coherence peak within the 8–13 Hz range was found between pallidal LFPs and EEG recorded at rest.

Conclusions

Neck/upper limbs voluntary movements and gait suppressed the GPi-LFPs—cortical-EEG coherence and differently impacted both EEG and LFPs low frequency activity. These findings suggest a selective modulation of the cortico-basal ganglia network activity in dystonia.

中文翻译：

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自由活动的肌张力障碍患者的苍白球和皮质振荡

 目标

旨在评估两名患有全身性肌张力障碍和苍白球深部脑刺激 (DBS) 的自由活动患者的苍白球局部场电位 (LFP) 活动与皮层振荡（休息时和多项运动任务期间）之间的相关性。

 材料和方法

选择两名患有孤立性全身肌张力障碍的女性进行双侧苍白球内肌 (GPi) DBS。电极植入后，在多项运动任务、步态和休息条件下，便携式脑电图 (EEG) 系统同时记录皮质活动和 GPi LFP 活动。刺激期间不进行记录。与每个特定运动相关的 EEG 和 LFP 信号耦合在一起，并按颈部/上肢运动和步态分组。计算功率谱密度 (PSD)、EEG-LFP 相干性（通过虚相干算子的包络）和 LFP-PSD 背景的 1/f 指数。

 结果

在这两名患者中，静息时的苍白 LFP PSD 的特点是显着的 4-12 Hz 活动。在 LFP 和 EEG 信号中，与休息相比，随意运动增加了 θ (θ) 频段 (4-7 Hz) 的活动。步态导致两名患者的苍白球活动中 θ 活动急剧增加，而脑电图信号则不太明显。在苍白 LFP 和静息时记录的脑电图之间发现了 8-13 Hz 范围内的相干性峰值。

 结论

颈部/上肢随意运动和步态抑制了 GPi-LFPs——皮质-EEG 一致性，并对 EEG 和 LFPs 低频活动产生不同的影响。这些发现表明肌张力障碍中皮质基底神经节网络活动的选择性调节。