Praamstra P, Plat F M
University of Nijmegen, The Netherlands.
J Cogn Neurosci. 2001 Jan 1;13(1):31-43. doi: 10.1162/089892901564153.
The response times in choice-reaction tasks are faster when the relative spatial positions of stimulus and response match than when they do not match, even when the spatial relation is irrelevant to response choice. This spatial stimulus-response (S--R) compatibility effect (i.e., the Simon effect) is attributed in part to the automatic activation of spatially corresponding responses, which need to be suppressed when the spatial location of stimulus and correct response do not correspond. The present study tested patients with Parkinson's disease and healthy control subjects in a spatial S--R compatibility task in order to investigate whether basal ganglia dysfunction in Parkinson's disease leads to disinhibition of direct visuomotor activation. High-density event-related brain potential recordings were used to chart the cortical activity accompanying attentional orientation and response selection. Response time measures demonstrated a failure to inhibit automatic response activation in Parkinson patients, which was revealed by taking into account a sequence-dependent modulation of the Simon effect. Event-related potential (ERP) recordings demonstrated that visuospatial orientation to target stimuli was accompanied by signal-locked activity above motor areas of the cortex, with similar latencies but an enhanced amplitude in patients compared to control subjects. The results suggest that inhibitory modulation of automatic, stimulus-driven, visuomotor activation occurs after the initial sensory activation of motor cortical areas. The failed inhibition in Parkinson's disease appears therefore related to a disturbance in processes that prevent early attention-related visuomotor activation, within motor areas, from actually evoking a response.
在选择反应任务中，当刺激与反应的相对空间位置匹配时，反应时间比不匹配时更快，即使空间关系与反应选择无关。这种空间刺激-反应（S-R）兼容性效应（即西蒙效应）部分归因于空间对应反应的自动激活，当刺激的空间位置与正确反应不对应时，这种激活需要被抑制。本研究在空间S-R兼容性任务中测试了帕金森病患者和健康对照者，以调查帕金森病中的基底神经节功能障碍是否导致直接视觉运动激活的去抑制。使用高密度事件相关脑电位记录来描绘伴随注意力定向和反应选择的皮层活动。反应时间测量表明，帕金森病患者无法抑制自动反应激活，这是通过考虑西蒙效应的序列依赖性调制揭示的。事件相关电位（ERP）记录表明，对目标刺激的视觉空间定向伴随着皮层运动区上方的信号锁定活动，与对照者相比，患者的潜伏期相似，但幅度增强。结果表明，对自动的、刺激驱动的视觉运动激活的抑制性调制发生在运动皮层区域的初始感觉激活之后。因此，帕金森病中抑制失败似乎与运动区域内阻止早期与注意力相关的视觉运动激活实际引发反应的过程紊乱有关。
