Lebrun N, Clochon P, Etévenon P, Lambert J, Baron J C, Eustache F
INSERM U320, Université de Caen, Boulevard H. Becquerel, B.P. 5229, F-14074 cedex, Caen, France.
Brain Res Cogn Brain Res. 2001 Apr;11(2):235-48. doi: 10.1016/s0926-6410(00)00078-1.
The aim of this paper was to investigate and compare the EEG mechanisms underlying the perceptual and semantic processes involved in environmental and language sounds perception by manipulating the degree of identification of sounds and using the ERD (event-related desynchronization) method in healthy subjects. Four types of stimuli were analyzed: meaningful environmental sounds, meaningless sounds, words and non-words. We report many similarities in the ERDs and ERSs (event-related synchronizations) patterns among all stimuli, with: (i) similar time-course of ERDs and ERSs between meaningful environmental sounds and words, and between meaningless sounds and non-words; (ii) similar topography of the maximal ERDs for meaningful environmental sounds, words and non-words; and (iii) same right posterior ERSs for all four stimuli. However, differences were also observed: (i) in time-course, with earlier ERSs for meaningless than meaningful stimuli, whether environmental or verbal; and (ii) in topography, with ERDs predominating in left and right hemisphere channels for meaningful and meaningless environmental sounds, respectively; (iii) ERSs predominating in the left temporal channel for non-words and in the left posterior and right frontal channels for meaningless sounds. The results of this study suggest that meaningful stimuli involve greater and longer-lasting semantic processes than meaningless stimuli, while the occurrence of ERSs for the latter points to the possible involvement of an inhibitory processing of semantic representations. Finally, the findings concerning the comparison between verbal and non verbal stimuli suggest the involvement of left-lateralized phonological and semantic processes for the former, and more distributed neurocognitive processes in both hemispheres for the latter although with predominant left laterality for their semantic processing.
本文旨在通过操控声音的识别程度，并在健康受试者中使用事件相关去同步化（ERD）方法，研究和比较环境声音与语言声音感知中涉及的感知和语义过程背后的脑电图机制。分析了四种类型的刺激：有意义的环境声音、无意义的声音、单词和非单词。我们报告了所有刺激在事件相关去同步化（ERD）和事件相关同步化（ERS）模式上的许多相似之处，包括：（i）有意义的环境声音与单词之间，以及无意义的声音与非单词之间，ERD和ERS的时间进程相似；（ii）有意义的环境声音、单词和非单词的最大ERD的地形图相似；（iii）所有四种刺激在右后部位的ERS相同。然而，也观察到了差异：（i）在时间进程方面，无论是环境声音还是语言声音，无意义刺激的ERS都比有意义刺激更早出现；（ii）在地形图方面，有意义和无意义的环境声音分别在左半球和右半球通道中以ERD为主；（iii）非单词在左颞叶通道中以ERS为主，无意义声音在左后和右额叶通道中以ERS为主。本研究结果表明，有意义的刺激比无意义的刺激涉及更大且更持久的语义过程，而后者出现的ERS表明语义表征可能参与了抑制性加工。最后，关于语言和非语言刺激比较的研究结果表明，前者涉及左侧化的语音和语义过程，而后者在两个半球中涉及更广泛分布的神经认知过程，尽管其语义加工以左侧为主。
