Kim Kyung Hwan, Choi Jeong Woo, Yoon Jin
Department of Biomedical Engineering, College of Health Science, Yonsei University, 234 Maeji-ri, Heungup-myun, Wonju, Kangwon-do, 220-710, South Korea.
Brain Res. 2009 Sep 29;1291:82-91. doi: 10.1016/j.brainres.2009.07.044. Epub 2009 Jul 23.
The difference in cortical mechanisms underlying processing different languages has been of great interest. Exploration of local and global functional connections between neuronal activities originating from task-relevant areas can contribute to a more complete understanding on these processes. Semantic processing is known to involve frontal and parietal activities, and thus, functional connection between anterior-posterior regions is expected during semantic processing of visually presented words. The major purpose of this study is to investigate whether a substantial difference in gamma-band phase synchronization (GBPS) is observed during semantic processing of visually presented words from primary (Korean) and secondary (English) languages. Conventional ERP component and evoked gamma-band activity (eGBA) analyses were also performed. Word pairs with closely-related or unrelated meanings were presented to 14 Korean subjects so that N400 event-related potential (ERP) component was evoked. Other components, such as P1, N1, and late positive component, could also be identified. The N1 was shown to be larger for Korean. Response times and N400 latencies were significantly faster for Korean. eGBAs were significantly smaller in response to English at ~100 ms poststimulus, and latencies were considerably delayed. We verified significant GBPS from anterior-posterior electrode pairs, and substantial difference between the two languages emerged in the GBPS pattern during the 200-350 ms period where significant GPBS was observed from more electrode pairs for Korean. This finding indicates that differences in cortical activities due to language differences are more evident in inter-regional connectivity during semantic analysis than during other stages, such as orthographic processing.
处理不同语言时皮质机制的差异一直备受关注。探索源自任务相关区域的神经元活动之间的局部和全局功能连接，有助于更全面地理解这些过程。已知语义处理涉及额叶和顶叶活动，因此，在对视觉呈现的单词进行语义处理时，前后区域之间预计会存在功能连接。本研究的主要目的是调查在对主要语言（韩语）和次要语言（英语）的视觉呈现单词进行语义处理期间，是否观察到伽马波段相位同步（GBPS）存在显著差异。还进行了传统的ERP成分和诱发伽马波段活动（eGBA）分析。向14名韩国受试者呈现意义密切相关或不相关的单词对，从而诱发N400事件相关电位（ERP）成分。还可以识别其他成分，如P1、N1和晚期正成分。结果显示，韩语的N1更大。韩语的反应时间和N400潜伏期明显更快。在刺激后约100毫秒时，对英语的eGBA明显更小，潜伏期明显延迟。我们验证了前后电极对之间存在显著的GBPS，并且在200 - 350毫秒期间，两种语言之间在GBPS模式上出现了显著差异，在此期间，韩语从更多电极对观察到显著的GBPS。这一发现表明，在语义分析过程中，由于语言差异导致的皮质活动差异在区域间连接方面比在其他阶段（如正字法处理）更为明显。
