Brain responses to nouns, verbs and class-ambiguous words in context
Brain responses to nouns, verbs and class-ambiguous words in context
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DOI：
10.1093/brain/123.12.2552
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发表时间：
2000-12-01
期刊：
影响因子：
14.5
通讯作者：
Kutas, M
中科院分区：
文献类型：
--
作者：
Federmeier, KD;Segal, JB;Kutas, M
最近的神经心理学和成像数据表明，不同的大脑网络涉及不同词类的处理，名词主要与后部、视觉对象处理区域相关，动词与额叶、运动处理区域相关。然而，由于大多数这些研究都是孤立地检查单词，因此这种基于解剖学的表征差异（如果有的话）对于句子中这些项目的处理的后果仍不清楚。此外，在某些语言中，许多单词（例如“饮料”）是类别模糊的，即它们可以根据上下文发挥任一作用，并且尚不清楚大脑如何存储和使用与上下文中的此类词汇项相关的信息。我们通过记录事件相关电位（ERP）来检查这些问题，以响应明确的名词（例如“啤酒”）、明确的动词（例如“吃”）、类模糊词和伪词，在两种类型的最小对比句子上下文中用作名词或动词：名词预测（例如“约翰想要[目标]但是...”）和动词预测（“约翰想要”到[目标]但是......'）。我们的结果表明，名词和动词的神经处理本质是刺激类型及其所扮演的角色的函数。即使上下文完全指定了它们的角色，词类模糊的项目与额叶区域中明确的项目也有大约 150 毫秒的差异。此外，虽然伪词用作动词时比用作名词时会引发更大的 N400，但明确名词和用作名词的歧义词分别比明确动词和用作动词的歧义词引发更多的额中心否定性。此外，明确的动词会引发左偏、前部积极性（类似于 200 毫秒），这是任何其他刺激类型都未观察到的，尽管只有当这些项目被适当地用作动词时（即在动词预测上下文中）。总之，观察到的对词汇项的反应的神经活动模式取决于它们作为动词或名词的一般概率以及它们在任何给定句子中所扮演的特定角色。这不仅仅意味着参与存储和处理的大脑网络之间存在简单的双向区别。经验以及在线语言处理过程中的上下文清楚地塑造了名词和动词的神经表征，因此不存在单一的词类神经标记。我们的结果进一步表明，脑损伤后观察到的基于词类的分离的存在和性质同样可能是刺激类型及其发生上下文的函数，因此必须进行相应的评估。
Recent neuropsychological and imaging data have implicated different brain networks in the processing of different word classes, nouns being linked primarily to posterior, visual object-processing regions and verbs to frontal, motor-processing areas. However, as most of these studies have examined words in isolation, the consequences of such anatomically based representational differences, if any, for the processing of these items in sentences remains unclear. Additionally, in some languages many words (e.g.'drink') are class-ambiguous, i.e. they can play either role depending on context, and it is not yet known how the brain stores and uses information associated with such lexical items in context. We examined these issues by recording event-related potentials (ERPs) in response to unambiguous nouns (e.g. 'beer'), unambiguous verbs (e.g.'eat') class-ambiguous words and pseudowords used as nouns or verbs within two types of minimally contrastive sentence contexts: noun-predicting (e.g.'John wanted THE [target] but...') and verb-predicting ('John wanted TO [target] but...'). Our results indicate that the nature of neural processing for nouns and verbs is a function of both the type of stimulus and the role it is playing. Even when the context completely specifies their role, word class-ambiguous items differ from unambiguous ones over frontal regions by similar to 150 ms. Moreover, whereas pseudowords elicit larger N400s when used as verbs than when used as nouns, unambiguous nouns and ambiguous words used as nouns elicit more frontocentral negativity than unambiguous verbs and ambiguous words used as verbs, respectively. Additionally, unambiguous verbs elicit a left-lateralized, anterior positivity (similar to 200 ms) not observed for any other stimulus type, though only when these items are used appropriately as verbs (i.e. in verb-predicting contexts). In summary, the pattern of neural activity observed in response to lexical items depends on their general probability of being a verb or a noun and on the particular role they are playing in any given sentence. This implicates more than a simple two-way distinction of the brain networks involved in their storage and processing. Experience, as well as context during on-line language processing, clearly shapes the neural representations of nouns and verbs, such that there is no single neural marker of word class. Our results further suggest that the presence and nature of the word class-based dissociations observed after brain damage are similarly likely to be a function of both the type of stimulus and the context in which it occurs, and thus must be assessed accordingly.