Department of Neurosciences University of California, San Diego.
J Cogn Neurosci. 1989 Winter;1(1):38-49. doi: 10.1162/jocn.1989.1.1.38.
Long-latency components of event-related brain potentials (ERPs) recorded from subjects reading meaningful text are sensitive to semantic relationships among the major lexical items of sentences. In particular, the N400 components are enlarged to words that are semantically unrelated to or incongruous with the context provided by preceding items in a sentence. The present experiment was aimed at finding out whether this inverse relationship between N400 amplitude and semantic association would extend to situations where words were presented in isolated pairs, using a design that dissociated changes in N400 from confounding ERP waves elicited by active decision making. KRP's were recorded to 320 word pairs presented to eleven subjects. Each pair of words was followed by a letter, and subjects made a differential response according to whether or not the letter had been present in either of the words. After the ERP recording session, subjects rated the degree of semantic association between the words in each pair. ERP averages were formed on the basis of the subjects' ratings and on the basis of normative, a priori categories. For both types of averages the N400 amplitude was found to be a sensitive index of semantic association, even though the association was incidental to the subject's assigned task. These findings suggest the utility of the N400 measure in studies of semantic priming and as a probe of the automaticity of contextual influences in language processing.
事件相关脑电位（ERPs）的长潜伏期成分记录了受试者阅读有意义的文本，这些成分对句子中主要词汇项之间的语义关系敏感。特别是，N400 成分会扩大到与句子中前面的项目所提供的语境语义上不相关或不一致的单词。本实验旨在发现 N400 振幅与语义关联之间的这种反比关系是否会扩展到单词以孤立对形式呈现的情况，使用一种设计，将 N400 的变化与由主动决策引起的混淆 ERP 波分开。向 11 名受试者呈现了 320 对单词，并记录了 KRP。每对单词后面都跟着一个字母，根据该字母是否出现在单词中的任意一个，受试者做出不同的反应。在 ERP 记录会议之后，受试者对每对单词之间的语义关联程度进行了评分。根据受试者的评分和规范的先验类别形成了 ERP 平均值。对于这两种平均值，N400 振幅都被发现是语义关联的敏感指标，即使这种关联与受试者的任务分配无关。这些发现表明，N400 测量在语义启动研究中以及作为语言处理中语境影响自动性的探针是有用的。
