Stimulus context determines P3a and P3b
Stimulus context determines P3a and P3b
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DOI：
10.1017/s0048577298961479
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发表时间：
1998-01-01
期刊：
影响因子：
3.7
通讯作者：
Polich, J
中科院分区：
文献类型：
--
作者：
Katayama, J;Polich, J
使用三刺激古怪范式评估目标(0.10)、非目标(0.10)和标准音调(0.80)的P300差异，其中参与者仅对目标做出反应(n=12)。目标/标准(容易或困难)和非目标/标准(大或小)螺距差被正交处理。在所有条件下，目标声调都会诱发顶叶P300，这只受目标/标准辨别易感性的影响。在易/大和难/小条件下，非靶点诱发的顶区P300小于靶点，而在易/小条件下，诱发的事件相关电位与标准值相近。然而，在困难/大的条件下，非靶点刺激引起P300(P3a)的前峰和早期成分。研究结果表明，目标P300不受非靶标刺激结构的影响，而非靶标P300的结果直接由刺激背景决定。文中还讨论了其理论意义。
P300 differences for target (.10), nontarget (.10), and standard tones (.80) were assessed using a three-stimulus oddball paradigm in which participants responded only to the target (n = 12). Target/standard (easy or difficult) and nontarget/standard (large or small) pitch differences were manipulated orthogonally. In all conditions, target tones elicited a parietal P300, which was affected only by the target/standard discrimination ease. Nontarget in the easy/large and difficult/small conditions elicited a parietal but smaller P300 than the target but in the easy/small condition elicited similar ERPs to the standard. However, nontarget stimuli in the difficult/large condition elicited an anterior maximum and earlier P300 (P3a) component. The findings suggest that target P300s are not influenced by the nontarget stimulus configuration, whereas the nontarget P300 outcomes are determined directly by the stimulus context. The theoretical implications are discussed.