Cognitive Brain Research Unit, Cognitive Science, Institute of Behavioural Sciences, University of Helsinki, Finland.
Cortex. 2013 Nov-Dec;49(10):2758-71. doi: 10.1016/j.cortex.2013.08.007. Epub 2013 Aug 27.
We investigated neural distinctions between inflectional and derivational morphology and their interaction with lexical frequency using the mismatch negativity (MMN), an established neurophysiological index of experience-dependent linguistic memory traces and automatic syntactic processing. We presented our electroencephalography (EEG) study participants with derived and inflected words of variable lexical frequencies against their monomorphemic base forms in a passive oddball paradigm, along with acoustically matched pseudowords. Sensor space and distributed source modelling results showed that at 100-150 msec after the suffix onset, derived words elicited larger responses than inflected words. Furthermore, real derived words showed advantage over pseudo-derivations and frequent derivations elicited larger activation than less frequent ones. This pattern of results is fully in line with previous research that explained lexical MMN enhancement by an activation of strongly connected word-specific long-term memory circuits, and thus suggests stronger lexicalisation for frequently used complex words. At the same time, a strikingly different pattern was found for inflectional forms: higher response amplitude for pseudo-inflections than for real inflected words, with no clear frequency effects. This is fully in line with previous MMN results on combinatorial processing of (morpho)syntactic stimuli: higher response to ungrammatical morpheme strings than grammatical ones, which does not depend on the string's surface frequency. This pattern suggests that, for inflectional forms, combinatorial processing route dominates over whole-form storage and access. In sum, our results suggest that derivations are more likely to form unitary representations than inflections which are likely to be processed combinatorially, and imply at least partially distinct brain mechanisms for the processing and representation of these two types of morphology. These dynamic mechanisms, underpinned by perisylvian networks, are activated rapidly, at 100-150 msec after the information arrives at the input, and in a largely automatic fashion, possibly providing neural basis for the first-pass morphological processing of spoken words.
我们使用失匹配负波（MMN）研究了屈折和派生形态之间的神经差异及其与词汇频率的相互作用，MMN 是一种已建立的神经生理指标，用于反映经验依赖性语言记忆痕迹和自动句法处理。我们在被动性Oddball 范式中向脑电图（EEG）研究参与者展示了具有不同词汇频率的派生词和屈折词，以及与其单词语素基形式相对应的听觉匹配的伪词。传感器空间和分布式源建模结果表明，在后缀开始后 100-150 毫秒，派生词比屈折词引起更大的反应。此外，真实的派生词比虚假派生词具有优势，而高频派生词比低频派生词引起更大的激活。这种结果模式完全符合先前的研究，该研究通过激活强连接的特定于单词的长期记忆电路来解释词汇 MMN 增强，这表明经常使用的复杂词具有更强的词汇化。同时，对于屈折形式，我们发现了截然不同的模式：虚假屈折词的反应幅度高于真实屈折词，而没有明显的频率效应。这完全符合以前关于（形态）句法刺激组合处理的 MMN 结果：对不合语法的语素串的反应高于对语法的语素串的反应，而不受字符串的表面频率的影响。这种模式表明，对于屈折形式，组合处理途径优于整体形式存储和访问。总之，我们的结果表明，派生词比屈折词更有可能形成单一的表示，而屈折词更可能以组合的方式进行处理，这至少部分地暗示了两种类型的形态的处理和表示所涉及的不同大脑机制。这些动态机制受周围皮层网络的支持，在信息到达输入后 100-150 毫秒内迅速激活，并以很大程度上自动的方式激活，可能为口语单词的第一遍形态处理提供神经基础。
