Schubert T, Volkmann J, Müller U, Sturm V, Voges J, Freund H-J, Von Cramon D Y
Max Planck Institute of Cognitive Neuroscience, Leipzig, Germany.
Exp Brain Res. 2002 May;144(1):8-16. doi: 10.1007/s00221-002-1020-1. Epub 2002 Mar 2.
Basal ganglia-thalamocortical circuits play an important role in movement preparation and execution. Tracer, single-cell, and lesion studies in monkeys suggest the existence of topologically segregated motor and nonmotor basal ganglia cortical circuits. In this study we used deep brain stimulation (DBS) of the posteroventrolateral globus pallidus internus (GPi) in patients with Parkinson's disease to elucidate the function of the GPi in human sensorimotor behavior. This question was investigated by comparing the influence of DBS on patients' performance in various reaction-time tasks that differed with respect to cognitive but not motor requirements. As a main result, DBS improved performance on the different tasks independently of the complexity of the involved cognitive processing functions. Furthermore, the observed effects did not depend on the modality of the processed information. These results suggest that the functional state of the posteroventrolateral GPi selectively affects the motor stage in simple sensorimotor acts, because this stage was the only stage involved in all investigated tasks. In addition to DBS, we manipulated the levodopa medication state of the PD patients. In contrast to DBS, levodopa effects on reaction times were less consistent. Levodopa improved reaction times in choice reaction tasks significantly, while affecting reaction times in a simple reaction task to a lesser extent. Error analysis revealed that the medication-dependent reaction-time improvement in the choice reaction tasks was accompanied by an increase in errors, suggesting a shift of the speed-accuracy criteria of the patients. A similar pattern of results was not observed for the DBS effects. Taken together, our data are in agreement with recent findings in monkeys that indicate a topological organization of the GPi in which motor functions are localized in posterolateral regions apart from cognitive regions. Furthermore, our data show a way to uncover the subcortical-cortical circuitry serving human sensorimotor behavior.
基底神经节 - 丘脑皮质环路在运动准备和执行中起重要作用。对猴子进行的示踪、单细胞和损伤研究表明，存在拓扑分离的运动和非运动基底神经节皮质环路。在本研究中，我们对帕金森病患者的腹后外侧苍白球内侧部（GPi）进行深部脑刺激（DBS），以阐明GPi在人类感觉运动行为中的功能。通过比较DBS对患者在各种反应时间任务中的表现的影响来研究这个问题，这些任务在认知要求上不同但运动要求相同。主要结果是，DBS改善了不同任务的表现，与所涉及的认知处理功能的复杂性无关。此外，观察到的效果不依赖于所处理信息的模态。这些结果表明，腹后外侧GPi的功能状态选择性地影响简单感觉运动行为中的运动阶段，因为这个阶段是所有研究任务中唯一涉及的阶段。除了DBS，我们还操纵了帕金森病患者的左旋多巴用药状态。与DBS不同，左旋多巴对反应时间的影响不太一致。左旋多巴显著改善了选择反应任务中的反应时间，而对简单反应任务中反应时间的影响较小。错误分析表明，选择反应任务中依赖药物的反应时间改善伴随着错误增加，这表明患者的速度 - 准确性标准发生了变化。DBS效果未观察到类似的结果模式。综上所述，我们的数据与最近在猴子中的发现一致，这些发现表明GPi存在拓扑组织，其中运动功能位于后外侧区域，与认知区域分开。此外，我们的数据展示了一种揭示服务于人类感觉运动行为的皮质下 - 皮质环路的方法。
