Connolly J F, Stewart S H, Phillips N A
Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
Brain Lang. 1990 Aug;39(2):302-18. doi: 10.1016/0093-934x(90)90016-a.
Ten English speaking subjects listened to sentences that varied in sentential constraint (i.e., the degree to which the context of a sentence predicts the final word of that sentence) and event-related potentials (ERPs) were recorded during the presentation of the final word of each sentence. In the Control condition subjects merely listened to the sentences. In the Orthographic processing condition subjects merely listened to the sentences. In the Orthographic processing condition subjects decided, following each sentence, whether a given letter had been present in the final word of the preceding sentence. In the Phonological processing condition the subjects judged whether a given speech sound was contained in the terminal word. In the Semantic processing condition subjects determined whether the final word was a member of a given semantic category. A previous finding in the visual modality that the N400 component was larger in amplitude for low constraint sentence terminations than for high was extended to the auditory modality. It was also found that the amplitude of a N200-like response was similarly responsive to contextual constraint. The hypothesis that N400 amplitude would vary significantly with the depth of processing of the terminal word was not supported by the data. The "N200" recorded in this language processing context showed the classic frontocentral distribution of the N200. The N400 to spoken sentences had a central/centroparietal distribution similar to the N400 in visual modality experiments. It is suggested that the N400 obtained in these sentence contexts reflects an automatic semantic processing of words that occurs even when semantic analysis is not required to complete a given task. The cooccurrence and topographical dissimilarity of the "N200" and N400 suggest that the N400 may not be a delayed or a generic N200.
十名说英语的受试者听了句子约束程度各异的句子（即句子上下文预测该句最后一个单词的程度），并在每个句子最后一个单词呈现期间记录了事件相关电位（ERP）。在控制条件下，受试者只是听句子。在正字法加工条件下，受试者只是听句子。在正字法加工条件下，受试者在听完每个句子后，判断给定字母是否出现在前一个句子的最后一个单词中。在语音加工条件下，受试者判断给定语音是否包含在最后一个单词中。在语义加工条件下，受试者确定最后一个单词是否属于给定的语义类别。之前在视觉模态中的一项发现，即低约束性句子结尾的N400成分振幅比高约束性句子结尾的更大，被扩展到了听觉模态。还发现类似N200的反应的振幅对上下文约束同样敏感。N400振幅会随最后一个单词加工深度显著变化的假设未得到数据支持。在这种语言加工背景下记录的“N200”显示出N200典型的额中央分布。对口语句子的N400具有与视觉模态实验中N400相似的中央/中央顶叶分布。有人提出，在这些句子情境中获得的N400反映了即使在不需要语义分析来完成给定任务时也会发生的单词自动语义加工。“N200”和N400的同时出现及地形差异表明，N400可能不是延迟的或一般的N200。
