Directorate of Psychology, Counselling and Psychotherapy, University of Salford, UK.
Cortex. 2011 Mar;47(3):332-41. doi: 10.1016/j.cortex.2010.01.011. Epub 2010 Feb 4.
Movement in Parkinson's disease (PD) is strongly influenced by sensory stimuli. Here, we investigated two features of visual stimuli known to affect response times in healthy individuals; the spatial location of an object (the spatial effect) and its action-relevance (the 'affordance' effect). Poliakoff et al. (2007) found that while PD patients show normal spatial effects, they do not show an additional affordance effect. Here we investigated whether these effects are driven by facilitation or inhibition, and whether the affordance effect emerges over a longer time-course in PD. Participants (24 PD and 24 controls) viewed either a lateralised door handle (affordance condition), a lateralised abstract stimulus (spatial condition), or a centrally presented baseline stimulus (baseline condition), and responded to a colour change in the stimulus occurring after 0 msec, 500 msec or 1000 msec. The colour change indicated whether to respond with the left or right hand, which were either spatially compatible or incompatible with the lateralised stimulus orientation in the affordance and spatial conditions. The baseline condition allowed us to assess whether compatibility effects were driven by facilitation of the compatible response or inhibition of the incompatible response. The results indicate that stimulus orientation elicited faster responses from the nearest hand. For controls, the affordance effect was stronger and driven by facilitation, whilst the spatial condition was driven by inhibition. In contrast, the affordance and spatial-compatibility effects did not differ between conditions in the PD group and both were driven by facilitation. This suggests that the PD group responded as if all stimuli were action-relevant, and may have implications for understanding the cueing of movement in PD.
帕金森病（PD）患者的运动受到感官刺激的强烈影响。在这里，我们研究了两个已知会影响健康个体反应时间的视觉刺激特征；物体的空间位置（空间效应）及其动作相关性（“可及性”效应）。Poliakoff 等人（2007 年）发现，虽然 PD 患者表现出正常的空间效应，但他们没有表现出额外的可及性效应。在这里，我们研究了这些效应是由促进还是抑制驱动的，以及在 PD 中可及性效应是否会在更长的时间内出现。参与者（24 名 PD 患者和 24 名对照组）观看了偏向一侧的门把手（可及性条件）、偏向一侧的抽象刺激（空间条件）或中央呈现的基线刺激（基线条件），并对刺激后 0 毫秒、500 毫秒或 1000 毫秒发生的颜色变化做出反应。颜色变化表明是用左手还是右手做出反应，在可及性和空间条件下，手的方向与偏向一侧的刺激方向是空间相容还是不相容。基线条件使我们能够评估兼容性效应是由相容反应的促进还是不相容反应的抑制驱动的。结果表明，刺激方向会使最近的手更快地做出反应。对于对照组，可及性效应更强，由促进驱动，而空间条件则由抑制驱动。相比之下，PD 组在两种条件下的可及性和空间兼容性效应没有差异，并且都是由促进驱动的。这表明 PD 组的反应就像是所有刺激都具有动作相关性，这可能对理解 PD 中运动的提示具有启示意义。
