Li Xiaoqing, Zhao Haiyan, Lu Yong
Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
PLoS One. 2014 Apr 22;9(4):e95834. doi: 10.1371/journal.pone.0095834. eCollection 2014.
Sentence comprehension involves timely computing different types of relations between its verbs and noun arguments, such as morphosyntactic, semantic, and thematic relations. Here, we used EEG technique to investigate the potential differences in thematic role computing and lexical-semantic relatedness processing during on-line sentence comprehension, and the interaction between these two types of processes. Mandarin Chinese sentences were used as materials. The basic structure of those sentences is "Noun+Verb+'le'+a two-character word", with the Noun being the initial argument. The verb disambiguates the initial argument as an agent or a patient. Meanwhile, the initial argument and the verb are highly or lowly semantically related. The ERPs at the verbs revealed that: relative to the agent condition, the patient condition evoked a larger N400 only when the argument and verb were lowly semantically related; however, relative to the high-relatedness condition, the low-relatedness condition elicited a larger N400 regardless of the thematic relation; although both thematic role variation and semantic relatedness variation elicited N400 effects, the N400 effect elicited by the former was broadly distributed and reached maximum over the frontal electrodes, and the N400 effect elicited by the latter had a posterior distribution. In addition, the brain oscillations results showed that, although thematic role variation (patient vs. agent) induced power decreases around the beta frequency band (15-30 Hz), semantic relatedness variation (low-relatedness vs. high-relatedness) induced power increases in the theta frequency band (4-7 Hz). These results suggested that, in the sentence context, thematic role computing is modulated by the semantic relatedness between the verb and its argument; semantic relatedness processing, however, is in some degree independent from the thematic relations. Moreover, our results indicated that, during on-line sentence comprehension, thematic role computing and semantic relatedness processing are mediated by distinct neural systems.
句子理解涉及及时计算其动词与名词论元之间不同类型的关系，如形态句法关系、语义关系和题元关系。在此，我们使用脑电图（EEG）技术来研究在线句子理解过程中题元角色计算和词汇语义相关性处理的潜在差异，以及这两种过程之间的相互作用。实验材料为汉语句子。这些句子的基本结构是“名词+动词+‘了’+双字词”，名词为初始论元。动词将初始论元区分为施事或受事。同时，初始论元与动词在语义上高度或低度相关。动词处的事件相关电位（ERP）结果显示：相对于施事条件，仅当论元与动词语义低度相关时，受事条件会诱发更大的N400；然而，相对于高相关性条件，无论题元关系如何，低相关性条件都会诱发更大的N400；尽管题元角色变化和语义相关性变化均诱发了N400效应，但前者诱发的N400效应分布广泛，在额电极处达到最大值，而后者诱发的N400效应具有后部分布。此外，脑电振荡结果表明，尽管题元角色变化（受事与施事）在β频段（15 - 30Hz）附近诱发功率下降，但语义相关性变化（低相关性与高相关性）在θ频段（4 - 7Hz）诱发功率增加。这些结果表明，在句子语境中，题元角色计算受到动词与其论元之间语义相关性的调节；然而，语义相关性处理在某种程度上独立于题元关系。此外，我们的结果表明，在在线句子理解过程中，题元角色计算和语义相关性处理由不同的神经系统介导。
