Khader Patrick, Scherag André, Streb Judith, Rösler Frank
Experimental and Biological Psychology, Philipps-University, 35032 Marburg, Germany.
Brain Res Cogn Brain Res. 2003 Jul;17(2):293-313. doi: 10.1016/s0926-6410(03)00130-7.
The aim of the present study was to enforce the priming of either nouns or verbs in order to evoke word-category-specific N400 effects. In two experiments two primes which were either a verb-noun or a noun-noun pair were followed by a semantically related or unrelated target which was a noun or verb, respectively. This target always completed the word sequence to a minimal phrase comprising verb, subject, and object (VNN or NNV triplets). In experiment I subjects judged the semantic relatedness of the target to the two primes, in experiment II subjects first generated an appropriate target of the required word category and then judged the semantic relatedness between self-generated word and target. ERPs were recorded from 124 scalp electrodes. In both experiments verbs and nouns as such evoked reliably distinct ERP topographies between 300 and 800 ms. With verbs in relation to nouns the amplitudes were most often found to be more positive over central to frontal or parietal areas and more negative over occipital and temporo-parietal areas. In contrast, N400 effects proved as topographically invariant for noun and verb targets in both experiments. The results suggest that access to noun and verb representations involves topographically distinct cell assemblies while the N400 effect seems to reflect semantic evaluation and integration processes which are more abstract and independent from a particular word category.
本研究的目的是强化名词或动词的启动，以诱发特定词类的N400效应。在两个实验中，两个启动词（一个动词-名词对或一个名词-名词对）之后分别跟着一个语义相关或不相关的目标词，目标词分别为名词或动词。这个目标词总是将单词序列完成到一个包含动词、主语和宾语的最小短语（VNN或NNV三元组）。在实验I中，受试者判断目标词与两个启动词的语义相关性；在实验II中，受试者首先生成所需词类的合适目标词，然后判断自我生成的词与目标词之间的语义相关性。通过124个头皮电极记录脑电图。在两个实验中，动词和名词本身在300至800毫秒之间都可靠地诱发了不同的脑电图地形图。与名词相比，动词的振幅在中央到额叶或顶叶区域通常更正向，在枕叶和颞顶叶区域更负向。相反，在两个实验中，N400效应在名词和动词目标上的地形分布是不变的。结果表明，获取名词和动词表征涉及地形上不同的细胞集合，而N400效应似乎反映了语义评估和整合过程，这些过程更抽象且独立于特定的词类。
