P3a, perceptual distinctiveness, and stimulus modality
P3a, perceptual distinctiveness, and stimulus modality
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DOI：
10.1016/s0926-6410(98)00009-3
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发表时间：
1998-07-01
期刊：
影响因子：
--
通讯作者：
Polich, J
中科院分区：
文献类型：
--
作者：
Comerchero, MD;Polich, J
研究采用了三种刺激的古怪范式(靶标、标准、非靶标)，即受试者对一个不常见的靶标做出反应，而这个靶标很难与频繁出现的标准区分开来。在不同的听觉和视觉通道条件下，一个不常见的非目标的刺激特征被操纵，使得它与目标的知觉区别被系统地改变。在低区分度和高区分度条件下，靶刺激P300波幅仅在顶极大于非靶刺激。相反，额叶/中央电极部位的非靶P3a波幅大于靶P300，且早于靶P300。与视觉刺激相比，目标和非目标之间的区分性操作产生了更大的听觉P3a成分。这一结果支持了以前的发现，即目标/标准刺激环境决定了听觉和视觉刺激模式的P3a产生，并表明诱导性刺激的独特性对P3a幅度有贡献。文中还讨论了理论意义。(C)1998 Elsevier Science B.V.保留所有权利。
A three-stimulus oddball paradigm (target, standard, nontarget) was employed in which subjects responded to an infrequent target, when its discrimination from the frequent standard was difficult. In separate auditory and visual modality conditions, the stimulus characteristics of an infrequent nontarget were manipulated such that its perceptual distinctiveness from the target was varied systematically. For both the low and high distinctiveness conditions, target stimulus P300 amplitude was larger than the nontarget only at the parietal electrode. In contrast, nontarget P3a amplitude was larger and earlier than the target P300 over the frontal/central electrode sites. The distinctiveness manipulation between the target and nontarget produced larger P3a component profiles for the auditory compared to visual stimuli. The results support previous findings that target/standard stimulus context determines P3a generation for both auditory and visual stimulus modalities and suggest that the distinctiveness of the eliciting stimulus contributes to P3a amplitude. Theoretical implications are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.