Horváth János
Institute of Cognitive Neuroscience and Psychology, RCNS, Hungarian Academy of Sciences, P.O.B. 398, Szondi u 83/85, 1394, Budapest, Hungary,
Psychol Res. 2014;78(3):339-48. doi: 10.1007/s00426-013-0507-7. Epub 2013 Aug 4.
Event-related potentials (ERPs) offer unique insights into processes related to involuntary attention changes triggered by rare, unpredictably occurring sensory events, that is, distraction. Contrasting ERPs elicited by distracters and frequent standard stimuli in oddball paradigms allowed the formulation of a three-stage model describing distraction-related processing: first, the distracting event is highlighted by a sensory filter. Second, attention is oriented towards the event, and finally, the task-optimal attention set is restored, or task priorities are changed. Although this model summarizes how distracting stimulus information is processed, not much is known about the cost of taking this exceptional route of processing. The present study demonstrates the impact of distraction on sensory processing. Participants performed a Go/NoGo tone-duration discrimination task, with infrequent pitch distracters. In the two parts of the experiment the duration-response mapping was reversed. Contrasts of distracter and standard ERPs revealed higher P3a- and reorienting negativity amplitudes for short than for long tones, independently from response type. To understand the cause of these asymmetries, short vs. long ERP contrasts were calculated. The ERP pattern showed that short standards elicited an attention-dependent offset response, which was abolished for short distracters. That is, the apparent P3a- and RON enhancements were caused by the removal of a task-related attentional sensory enhancement. This shows that the disruption of task-optimal attention set precedes the elicitation of the P3a, which suggests that P3a does not reflect a process driving the initial distraction-related attention change.
事件相关电位（ERPs）为研究由罕见、不可预测的感官事件引发的非自愿注意力变化（即分心）相关过程提供了独特视角。在Oddball范式中，对比分心刺激和频繁出现的标准刺激所引发的ERPs，有助于构建一个描述与分心相关处理过程的三阶段模型：首先，一个感官过滤器突出显示分心事件；其次，注意力转向该事件；最后，恢复任务最优注意力集，或改变任务优先级。尽管该模型总结了分心刺激信息的处理方式，但对于采用这种特殊处理路径的代价却知之甚少。本研究展示了分心对感官处理的影响。参与者执行了一个Go/NoGo音调持续时间辨别任务，其中包含不频繁出现的音高分心刺激。在实验的两个部分中，持续时间与反应的映射关系是相反的。分心刺激和标准ERPs的对比显示，与反应类型无关，短音调的P3a和重新定向负波振幅高于长音调。为了理解这些不对称性的原因，计算了短ERPs与长ERPs的对比。ERP模式表明，短标准刺激引发了一种注意力依赖的偏移反应，而短分心刺激则消除了这种反应。也就是说，明显的P3a和RON增强是由于去除了与任务相关的注意力感官增强。这表明，在P3a诱发之前，任务最优注意力集就已被破坏，这表明P3a并不反映驱动最初与分心相关的注意力变化的过程。
