Cognitive Brain Research Unit, Cognitive Science, Institute of Behavioural Sciences, University of Helsinki Helsinki, Finland.
Front Hum Neurosci. 2011 Jul 21;5:66. doi: 10.3389/fnhum.2011.00066. eCollection 2011.
The spatiotemporal dynamics of the neural processing of spoken morphologically complex words are still an open issue. In the current study, we investigated the time course and neural sources of spoken inflected and derived words using simultaneously recorded electroencephalography (EEG) and magnetoencephalography (MEG) responses. Ten participants (native speakers) listened to inflected, derived, and monomorphemic Finnish words and judged their acceptability. EEG and MEG responses were time-locked to both the stimulus onset and the critical point (suffix onset for complex words, uniqueness point for monomorphemic words). The ERP results showed that inflected words elicited a larger left-lateralized negativity than derived and monomorphemic words approximately 200 ms after the critical point. Source modeling of MEG responses showed one bilateral source in the superior temporal area ∼100 ms after the critical point, with derived words eliciting stronger source amplitudes than inflected and monomorphemic words in the right hemisphere. Source modeling also showed two sources in the temporal cortex approximately 200 ms after the critical point. There, inflected words showed a more systematic pattern in source locations and elicited temporally distinct source activity in comparison to the derived word condition. The current results provide electrophysiological evidence for at least partially distinct cortical processing of spoken inflected and derived words. In general, the results support models of morphological processing stating that during the recognition of inflected words, the constituent morphemes are accessed separately. With regard to derived words, stem and suffix morphemes might be at least initially activated along with the whole word representation.
口语形态复杂词的神经处理的时空动态仍是一个悬而未决的问题。在当前的研究中，我们使用同时记录的脑电图（EEG）和脑磁图（MEG）响应来研究口语屈折词和派生词的时间进程和神经源。十位参与者（以英语为母语的人）听了屈折词、派生词和单语素词，并判断它们的可接受性。EEG 和 MEG 响应与刺激开始和关键点（复杂词的后缀开始，单语素词的独特点）同步。ERP 结果表明，在关键点后约 200ms，屈折词比派生词和单语素词诱发了更大的左侧负性。MEG 响应的源建模显示，在关键点后约 100ms，在颞上区有一个双侧源，派生词在右半球诱发的源幅度强于屈折词和单语素词。源建模还显示在关键点后约 200ms 时在颞叶皮层中有两个源。在那里，与派生词条件相比，屈折词在源位置上显示出更系统的模式，并诱发了时间上不同的源活动。目前的结果为口语屈折词和派生词的至少部分不同的皮质处理提供了电生理证据。总的来说，这些结果支持了形态处理模型，即屈折词的识别过程中，构成的词素是单独访问的。关于派生词，词干和后缀词素可能至少在初始阶段与整个单词的表示一起被激活。
