Sharott Andrew, Grosse Pascal, Kühn Andrea A, Salih Farid, Engel Andreas K, Kupsch Andreas, Schneider Gerd-Helge, Krauss Joachim K, Brown Peter
Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
Brain. 2008 Feb;131(Pt 2):473-84. doi: 10.1093/brain/awm324. Epub 2008 Jan 4.
The pathophysiological mechanisms of primary dystonia have largely remained obscure. Yet there is one undeniable observation: lesioning or high-frequency stimulation of the internal segment of the globus pallidus (GP) ameliorates dystonic symptoms. The latter observation implicates abnormal pallidal activity in the genesis of primary dystonia. Recently, excessive oscillatory pallidal activity in the 3-10 Hz frequency range, synchronized with dystonic EMG, has been related to the occurrence of involuntary muscle activity in these patients. However, it is unclear whether this pathological synchronization is driven by GP, caused by re-afference from dystonic muscle, or due to a combination of these two processes. Here we used the Directed Transfer Function as a spectral measure to identify the degree and direction of coupling across time between GP and muscle in seven patients with primary dystonia. We show that pallidal local field potential activity <or= 10 Hz is coherent with dystonic movements, and that although the coupling between GP and activity in the sternocleidomastoid muscle is bidirectional, the drive from GP to muscle significantly outweighs that from muscle to GP. In addition, the net GP drive to muscle is not stable but fluctuates across time, in keeping with the dynamic nature of dystonic muscle activity.
原发性肌张力障碍的病理生理机制在很大程度上仍不清楚。然而，有一个不可否认的观察结果：毁损或高频刺激苍白球内侧段（GP）可改善肌张力障碍症状。后一观察结果表明原发性肌张力障碍的发生与苍白球活动异常有关。最近，在3-10Hz频率范围内过度的苍白球振荡活动，与肌张力障碍肌电图同步，已被认为与这些患者的不自主肌肉活动的发生有关。然而，尚不清楚这种病理性同步是由苍白球驱动、由肌张力障碍肌肉的再传入引起，还是由于这两个过程的结合。在这里，我们使用定向传递函数作为一种频谱测量方法，来确定7例原发性肌张力障碍患者苍白球与肌肉之间跨时间耦合的程度和方向。我们发现苍白球局部场电位活动≤10Hz与肌张力障碍运动是相干的，并且尽管苍白球与胸锁乳突肌活动之间的耦合是双向的，但从苍白球到肌肉的驱动明显超过从肌肉到苍白球的驱动。此外，从苍白球到肌肉的净驱动不稳定，而是随时间波动，这与肌张力障碍肌肉活动的动态性质一致。
