Stimulus context determines whether non-target stimuli are processed as task-relevant or distractor information
Stimulus context determines whether non-target stimuli are processed as task-relevant or distractor information
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DOI：
10.1016/j.clinph.2006.06.755
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发表时间：
2006-11
影响因子：
4.7
通讯作者：
Risa Sawaki;J. Katayama
中科院分区：
文献类型：
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作者：
Risa Sawaki;J. Katayama
目的采用视觉三刺激奇球范式（标准0.70，目标0.15，非目标0.15）诱发P300事件相关脑电位（ERP），探讨目标/标准刺激情境对非目标加工的影响。方法对目标/标准辨别难度（简单或困难）和非目标/目标相似度（相似或不相似）进行正交处理。参与者（N=13）被指示通过按下按钮来对每个不常见的目标刺激做出反应。结果所有任务条件下的目标刺激均诱发P3b， P3b仅受目标/标准辨别难度的影响。当目标/标准容易辨别时，相似非目标P3的振幅大于不相似非目标P3。相比之下，当目标/标准区分困难时，非目标刺激诱发P3a，不相似的P3a振幅大于相似的非目标。因此，非目标刺激的P300分量和目标相似性对每个P300分量的影响模式随着目标/标准刺激情境的变化而变化。结论目标/标准刺激情境影响刺激加工的注意集，从而决定非目标刺激被加工为任务相关信息还是分心信息。意义本研究结果对理解非目标加工中的认知修饰机制具有重要意义。
OBJECTIVEThe P300 event-related brain potential (ERP) was elicited using a visual three-stimulus oddball paradigm (standard 0.70, target 0.15, non-target 0.15) to examine how target/standard stimulus context affects non-target processing.METHODSTarget/standard discrimination difficulty (easy or difficult) and non-target /target similarity (similar or dissimilar) were manipulated orthogonally. Participants (N=13) were instructed to respond to each infrequent target stimulus by pressing a button.RESULTSTarget stimuli in all task conditions elicited P3b, which was affected only by the difficulty of target/standard discrimination. When target/standard discrimination was easy, the amplitude of non-target P3 was larger for similar than for dissimilar non-target. In contrast, when target/standard discrimination was difficult, non-target stimuli elicited P3a, the amplitude of which was larger for dissimilar than for similar non-target. Thus, the P300 component for non-target stimuli and the pattern of the effect of target similarity on each P300 component varied as a function of the target/standard stimulus context.CONCLUSIONSThe target/standard stimulus context influences the attentional set for stimulus processing such that it determines whether non-target stimuli are processed as task-relevant or distractor information.SIGNIFICANCEThe present results are important for understanding the mechanism of cognitive modification in non-target processing.