Wylie Scott A, Stout Julie C, Bashore Theodore R
Department of Neurology, University of Virginia, Charlottesville, VA, USA.
Neuropsychologia. 2005;43(7):1033-43. doi: 10.1016/j.neuropsychologia.2004.10.008. Epub 2005 Jan 8.
Response selection often occurs in a context of competition among conflicting responses. According to recent models, the basal ganglia may play an integral role in resolving this competition by focusing the selection and inhibition of responses. We hypothesized that basal ganglia dysfunction produced by Parkinson's disease (PD) disrupts selection among conflicting responses. Using a version of the Eriksen flanker task, we tested the specific prediction that individuals with PD would experience greater response interference when distractors in the visual field activate a response that conflicts with the target response. In addition, we investigated whether greater response interference induced by these distractors could actually reduce normal response time costs in PD when the task required production of the response opposite the target. Compared to 16 healthy controls (HC), 16 individuals with PD showed an exacerbated slowing when target and distracting stimuli corresponded to conflicting responses. No group differences occurred when targets and distractors corresponded to the same response. Furthermore, the slowing induced by the distractors was reduced in both groups, but more so in PD, when execution of a response opposite the target response (i.e. incompatible response) was required. Moreover, among individuals with PD, the magnitude of the interference produced by the distractors was related to clinical ratings of bradykinesia. These findings are consistent with the hypothesis that basal ganglia dysfunction due to Parkinson's disease disrupts processes that resolve response conflict.
反应选择通常发生在相互冲突的反应之间的竞争背景中。根据最近的模型，基底神经节可能通过聚焦反应的选择和抑制在解决这种竞争中发挥不可或缺的作用。我们假设帕金森病（PD）导致的基底神经节功能障碍会扰乱相互冲突的反应之间的选择。使用一种版本的埃里克森侧翼任务，我们测试了一个具体的预测，即当视野中的干扰物激活与目标反应相冲突的反应时，帕金森病患者会经历更大的反应干扰。此外，我们研究了当任务要求做出与目标相反的反应时，这些干扰物引起的更大反应干扰是否实际上可以减少帕金森病患者正常的反应时间成本。与16名健康对照者（HC）相比，16名帕金森病患者在目标刺激和干扰刺激对应相互冲突的反应时，表现出更严重的反应减慢。当目标和干扰物对应相同的反应时，两组之间没有差异。此外，当需要做出与目标反应相反的反应（即不相容反应）时，两组中干扰物引起的反应减慢都有所减少，但在帕金森病患者中减少得更多。此外，在帕金森病患者中，干扰物产生的干扰程度与运动迟缓的临床评分相关。这些发现与以下假设一致，即帕金森病导致的基底神经节功能障碍会扰乱解决反应冲突的过程。
