l-Dopa induces under-damped visually guided motor responses in Parkinson's disease
l-Dopa induces under-damped visually guided motor responses in Parkinson's disease
复制标题
DOI：
10.1007/s00221-010-2156-z
复制
发表时间：
2010-05-01
影响因子：
2
通讯作者：
McKeown, Martin J.
中科院分区：
文献类型：
--
作者：
Au, Wing-Lok;Lei, Ni;McKeown, Martin J.
帕金森病优先影响内部产生的运动，例如，从记忆中回忆起的运动，而外部提示的运动相对保留。然而，左旋多巴可能对视觉引导运动以及与错误相关的处理有影响。14名帕金森氏症（PD）受试者（服用和停用左旋多巴药物）以及10名正常对照者使用操纵杆执行跟踪任务。在离散的30s块中，实际跟踪误差的视觉反馈被衰减、放大或保持不变。采用二阶动力系统模型，以期望轨迹为输入，以实际运动性能为输出，表征每个受试者在每种条件下的运动性能。虽然总体均方根跟踪误差在两组之间没有显著差异，但运动表现的性质在两组之间存在显著差异。误差反馈的操作（改变了模型的固有频率）和左旋多巴的影响（影响了阻尼）之间产生了明显的分离。与正常对照相比，PD受试者用药前显著过阻尼，用药后显著过阻尼。我们解释我们的结果提示左旋多巴正常化代偿过度活跃的小脑活动在PD。
Parkinson's disease preferentially affects internally generated movements, e.g., movements recalled from memory, while externally cued movements are relatively preserved. However, l-dopa may have effects on visually guided movements as well as error-related processing. Fourteen Parkinson's disease (PD) subjects (on and off l-dopa medication) as well as ten normal controls performed a tracking task using a joystick. During discrete 30 s blocks, the visual feedback of the actual tracking errors were attenuated, amplified or unaltered. Second order dynamical system models, with the desired trajectory as the input and the actual motor performance as the output, were used to characterize the motor performance by the each subject under each condition. Although the overall root-mean-square tracking error did not significantly differ between groups, the nature of the motor performance differed significantly across groups. A clear dissociation was made between manipulations of error feedback-which altered the natural frequency of the models-and the effects of l-dopa, which affected damping. Compared to normal controls, PD subjects were significantly overdamped before medication and underdamped after medication. We interpret our results as being suggestive of l-dopa normalization of compensatory overactive cerebellar activity in PD.