Psychological Imaging Laboratory, Psychology, School of Natural Sciences, University of Stirling, UK.
Neuropsychologia. 2013 Aug;51(9):1742-8. doi: 10.1016/j.neuropsychologia.2013.05.003. Epub 2013 May 23.
The N400 is one of the most widely studied ERP components and has come to be viewed as an index of the semantic processing that relates distinct stimuli. In this study, we examine whether the N400 is sensitive to the associative relationship between distinct stimuli, and not the degree to which the stimuli share semantic features. We used previously established norms to parametrically vary the strength of linguistic association between words within word-pairs, while holding constant their degree of semantic congruency. This manipulation allowed us to compare N400s elicited by unrelated prime-target word-pairs (e.g. mirror-thumb) with N400s generated by related prime-target word-pairs of either moderate (e.g. camera-lens) or high (e.g. cherry-tree) degrees of association. We observed that larger N400 effects occurred for highly associated versus moderately associated pairs despite the fact that no differences in terms of semantic congruency existed between pairs belonging to the highly and moderately associated conditions. These findings demonstrate that the N400 can be modulated by associative relationships quite independently of semantics, and suggest that the N400 effect reflects processes sensitive to the contiguity of distinct elements within one's past experience and not their semantic properties per se.
N400 是最广泛研究的 ERP 成分之一，已被视为与不同刺激相关的语义处理的指标。在这项研究中，我们研究了 N400 是否对不同刺激之间的联想关系敏感，而不是刺激共享语义特征的程度。我们使用先前建立的规范，在保持语义一致性的同时，参数化地改变词对中词之间的语言关联强度。这种操作使我们能够比较由不相关的主导目标词对（例如 mirror-thumb）引起的 N400 与由具有中度（例如 camera-lens）或高度（例如 cherry-tree）关联程度的相关主导目标词对引起的 N400。我们观察到，高度关联的词对与中度关联的词对相比，N400 效应更大，尽管高度和中度关联条件下的词对在语义一致性方面没有差异。这些发现表明，N400 可以通过联想关系进行调节，而与语义无关，这表明 N400 效应反映了对一个人过去经验中不同元素连续性敏感的过程，而不是它们的语义属性本身。
