Department of Neurology, University Hospital Cologne, Köln, Germany.
Eur J Neurosci. 2010 Feb;31(3):491-8. doi: 10.1111/j.1460-9568.2010.07083.x. Epub 2010 Jan 25.
Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson's disease, although its precise mechanisms remain poorly understood. To gain further insight into the mechanisms underlying deep brain stimulation, we analysed the causal relationship between forearm muscle activity and local field potentials derived from the subthalamic nucleus. In 19 patients suffering from Parkinson's disease of the akinetic-rigid subtype, we calculated the squared partial directed coherence between muscles of the contralateral forearm and the subthalamic nucleus or zona incerta during both a rest and a hold condition of the arm. For both recording regions, data analysis revealed that, during the rest condition, electromyographic activity was significantly more often 'Granger-causal' for the local field potentials than the opposite causation. In contrast, during the hold condition, no significant difference was found in the occurrence of causalities. Contrary to the existing basal ganglia model and the current concept of Parkinson's disease pathophysiology, we found the subthalamic nucleus to receive more 'afferences' than it emitted 'efferences', suggesting that its role is more complex than a simple driving nucleus in the basal ganglia loop. Therefore, the effect of deep brain stimulation in the subthalamic nucleus could, at least in part, result from a blockade of pathological afferent input.
丘脑底核深部脑刺激是治疗帕金森病的有效方法，但其确切机制仍不清楚。为了更深入地了解深部脑刺激的机制，我们分析了来自丘脑底核的前臂肌肉活动与局部场电位之间的因果关系。在 19 名患有静止性震颤型帕金森病的患者中，我们在手臂休息和保持状态下计算了对侧前臂肌肉与丘脑底核或中间核之间的平方偏部分相干性。对于这两个记录区域，数据分析显示，在休息状态下，肌电图活动对局部场电位的“格兰杰因果关系”明显比相反的因果关系更为常见。相比之下，在保持状态下，因果关系的发生没有显著差异。与现有的基底神经节模型和当前的帕金森病病理生理学概念相反，我们发现丘脑底核接收的“传入”比它发出的“传出”多，这表明它的作用比基底神经节回路中的简单驱动核更为复杂。因此，丘脑底核深部脑刺激的效果至少部分可能是由于阻断了病理性传入输入。
