Department of Experimental Psychology, Ghent University, Belgium.
Department of Experimental Psychology, Ghent University, Belgium.
Neuropsychologia. 2012 Oct;50(12):2860-2868. doi: 10.1016/j.neuropsychologia.2012.08.014. Epub 2012 Aug 24.
Inhibition of a response affects the processing of subsequent stimuli. When a response has to be made to a stimulus to which a response was previously inhibited, response time increases. In this study, we investigated the neurophysiological underpinnings of this repetition priming phenomenon. We aimed at distinguishing between two possible mechanisms. Firstly, it could be that slowing after a successful inhibition trial originates at the response execution level and is due to the reactivation of the system responsible for motor inhibition interfering with execution of the go response. The second possibility is that interference occurs at the more abstract level of conflicting action goals or plans (i.e. "stop" and "go") that are activated prior to response execution. We analyzed activity over primary motor cortices and the parietal cortex in a stop signal task. Stimulus repetition led to a decrease in activity over primary motor cortices but irrespective of history of stopping. Stopping on the previous trial did affect the stimulus-locked parietal P300 only on repetition of the stimulus, mimicking the behavioral pattern. Furthermore, the P300 was lateralized and affected by both stimulus onset and response time, suggesting that the interference caused by inhibition priming is situated between stimulus perception and response execution. Taken together, these findings show that the prolonged response times to a stimulus that was previously successfully inhibited to, do not originate from reactivated suppression of motor output, but are caused by interference between a stop and a go goal in parietal cortex that hampers translation from stimulus to response.
抑制反应会影响对后续刺激的处理。当对先前被抑制的刺激做出反应时，反应时间会增加。在这项研究中，我们调查了这种重复启动现象的神经生理基础。我们旨在区分两种可能的机制。首先，成功抑制试验后的减速可能起源于反应执行水平，是由于负责运动抑制的系统重新激活，干扰了去反应的执行。第二种可能性是，干扰发生在更抽象的冲突动作目标或计划层面（即“停止”和“去”），这些目标或计划在反应执行之前被激活。我们在停止信号任务中分析了初级运动皮层和顶叶皮层的活动。刺激重复导致初级运动皮层的活动减少，但与停止的历史无关。上一个试验中的停止仅在刺激重复时影响刺激锁定的顶叶 P300，模仿行为模式。此外，P300 被侧化，并受到刺激起始和反应时间的影响，这表明抑制启动引起的干扰位于刺激感知和反应执行之间。总之，这些发现表明，对先前成功抑制的刺激的反应时间延长，并非源自运动输出的重新激活抑制，而是由顶叶皮层中停止和去目标之间的干扰引起的，这阻碍了从刺激到反应的转化。
