White Erin J, Nayman Candace, Dunkley Benjamin T, Keller Anne E, Valiante Taufik A, Pang Elizabeth W
Neurosciences and Mental Health, Sick Kids Research Institute, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.
Epilespy Research Program of the Ontario Brain Institute, Toronto, ON, Canada.
Front Psychol. 2018 Oct 12;9:1960. doi: 10.3389/fpsyg.2018.01960. eCollection 2018.
During speech, how does the brain integrate information processed on different timescales and in separate brain areas so we can understand what is said? This is the language binding problem. Dynamic functional connectivity (brief periods of synchronization in the phase of EEG oscillations) may provide some answers. Here we investigate time and frequency characteristics of oscillatory power and phase synchrony (dynamic functional connectivity) during speech comprehension. Twenty adults listened to meaningful English sentences and non-sensical "Jabberwocky" sentences in which pseudo-words replaced all content words, while EEG was recorded. Results showed greater oscillatory power and global connectivity strength (mean phase lag index) in the gamma frequency range (30-80 Hz) for English compared to Jabberwocky. Increased power and connectivity relative to baseline was also seen in the theta frequency range (4-7 Hz), but was similar for English and Jabberwocky. High-frequency gamma oscillations may reflect a mechanism by which the brain transfers and integrates linguistic information so we can extract meaning and understand what is said. Slower frequency theta oscillations may support domain-general processing of the rhythmic features of speech. Our findings suggest that constructing a meaningful representation of speech involves dynamic interactions among distributed brain regions that communicate through frequency-specific functional networks.
在言语过程中，大脑如何整合在不同时间尺度和不同脑区处理的信息，以便我们能够理解所说的内容？这就是语言绑定问题。动态功能连接（脑电图振荡相位的短暂同步期）可能提供一些答案。在这里，我们研究言语理解过程中振荡功率和相位同步（动态功能连接）的时间和频率特征。20名成年人在记录脑电图的同时，听取有意义的英语句子和无意义的“胡说诗”句子，其中用伪词替换了所有实词。结果显示，与“胡说诗”相比，英语在伽马频率范围（30 - 80赫兹）内具有更大的振荡功率和全局连接强度（平均相位滞后指数）。在theta频率范围（4 - 7赫兹）内也观察到相对于基线功率和连接性增加，但英语和“胡说诗”相似。高频伽马振荡可能反映了一种大脑传递和整合语言信息的机制，以便我们能够提取意义并理解所说内容。较慢频率的theta振荡可能支持言语节奏特征的一般领域处理。我们的研究结果表明，构建有意义的言语表征涉及通过特定频率功能网络进行通信的分布式脑区之间的动态相互作用。
