Beste Christian, Dziobek Isabel, Hielscher Horst, Willemssen Rita, Falkenstein Michael
IfADo, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
Eur J Neurosci. 2009 Feb;29(4):855-60. doi: 10.1111/j.1460-9568.2009.06621.x. Epub 2009 Feb 6.
Parkinson's disease (PD) is a neurodegenerative basal ganglia disorder accompanied by deficits in cognitive functions. One important executive function is the inhibition of responses. Due to basal ganglia damage, processes related to the selection of response are also dysfunctional. However, the relevance of deficits in response selection to processes related to response inhibition in PD is not clear. In this study we examined these processes by means of event-related potentials (ERPs) in two Go/Nogo tasks. In one task the stimulus-response mapping was compatible and in the other task it was incompatible with the meaning of the stimuli. The behavioural results show that PD patients were unaffected in the compatible response inhibition task but encountered problems in the incompatible one. In the ERPs the N2, generally reflecting response selection, was delayed for the PD compared to the control group. This suggests that response selection is delayed in PD. Moreover, the N2 was specifically enhanced in Nogo trials. This indicates that premotor inhibition, which is probably reflected by the Nogo-N2, is intensified in PD. The P3 was specifically attenuated and delayed after Nogo stimuli in the incompatible condition for PDs. Assuming that the Nogo-P3 reflects the evaluation of successful motor inhibition, our data show that this process is attenuated and delayed in PD but mainly in the incompatible task. The results suggest that inhibitory deficits in PD are only evident in complex (incompatible) stimulus-response mappings. These effects are probably due to an overstrain of striatal processes.
帕金森病（PD）是一种伴有认知功能缺陷的神经退行性基底神经节疾病。一种重要的执行功能是反应抑制。由于基底神经节受损，与反应选择相关的过程也出现功能障碍。然而，在帕金森病中，反应选择缺陷与反应抑制相关过程之间的关联尚不清楚。在本研究中，我们通过两个Go/Nogo任务中的事件相关电位（ERP）来研究这些过程。在一个任务中，刺激-反应映射是兼容的，而在另一个任务中，它与刺激的意义不兼容。行为结果表明，帕金森病患者在兼容反应抑制任务中未受影响，但在不兼容任务中遇到问题。在ERP中，与对照组相比，通常反映反应选择的N2在帕金森病患者中延迟出现。这表明帕金森病患者的反应选择延迟。此外，在Nogo试验中，N2特异性增强。这表明，可能由Nogo-N2反映的运动前抑制在帕金森病中增强。在不兼容条件下，帕金森病患者在Nogo刺激后，P3特异性减弱并延迟出现。假设Nogo-P3反映了成功运动抑制的评估，我们的数据表明，这一过程在帕金森病中减弱并延迟，但主要在不兼容任务中。结果表明，帕金森病中的抑制缺陷仅在复杂（不兼容）的刺激-反应映射中明显。这些影响可能是由于纹状体过程过度紧张所致。
