汉语听觉语言信号和韵律信号处理的fMRI研究

An fMRI Study on the Processing of Chinese Auditory Language Signals and Prosodic Signals

目的韵律作为语言层级结构之一,在语言发展中至关重要。将韵律信号用于言语康复治疗和外语学习中,取得了显著效果。但大脑如何处理语言信号与语言韵律信号,以及二者处理机制异同有待进一步探讨。本研究旨在通过功能磁共振成像,探索中国大学生处理汉语语言信号与语言韵律信号时的脑区分布特征。方法30例平均年龄25岁,右利手,汉语为母语的大学生入组。句子音频信号通过低通滤波器,320 Hz以下的低频率语言韵律信号被保留,得到两组不同信号:双耳低通过滤(FF)和双耳不过滤(NF)。被试分别听两组不同的音频信号,同时进行两组组块设计的BOLD-fMRI成像。影像数据通过SPM12软件离线处理之后,进行组内单样本t检验、组间双样本t检验、偏侧化指数计算,以此获得大脑处理语音信号时的组内和组间大脑激活区分布及强度的共性和差异,以及偏侧化表现。结果双侧颞上回和颞中回在两组信号中都出现了激活(P<0.001)。双侧额下回、额中回在FF组中表现出明显激活(P<0.001)。FF组中的右侧额中回较NF组具有明显差异性(P<0.006)。两组信号激活的额下回、额中回都表现出了明显的右侧化趋势。结论两种语音信号所激活的脑区有部分重叠,但也有各自特异的激活区。NF组激活区范围较集中,考虑对未过滤母语信号的熟悉程度有关。双侧颞上回和颞中回与语音信号的接受、语言音韵编码和理解相关。韵律和语言信号无法完全分离,因此在处理FF组时双侧额下回和额中回也参与了语音和语义处理,且右侧额中回发挥了重要作用。总而言之,脑的语言功能区和其他功能区一样,并非简单的一一对应关系,而是以复杂的整体神经网络形式发挥作用。

Objective Prosody,as one level of the language hierarchy,is essential in language development.Prosodic signals were applied to speech rehabilitation and foreign language learning,indicating that prosody was effective in improving speech production.But these findings entail further explorations on how the brain processes language signals and linguistic prosody,as well as the similarities and differences of the two processing mechanisms.The current study aims at exploring the activation patterns of the brain regions while Chinese university students are processing Chinese language signals and prosodic signals by using functional MRI.Methods 30 university students with an average age of 25,right handed,and regarding Chinese as the first language were enrolled in the study.Sentence audio signals were filtered through a low pass filter,and frequencies below 320 Hz were retained as linguistic prosody signals.Two configurations of signals were organized as low pass filtered in both channels(FF)and non filtered in both channels(NF).Participants listened to two configurations of signals,and two runs of BOLD fMRI scanning were performed simultaneously.After scanning,the image data were processed offline by the SPM12 software.One sample t-tests,two sample t-tests,and the lateralization index were calculated to observe the distribution,intensity,and lateralization patterns of the activated brain areas when processing the signals.Results Bilateral superior and middle temporal gyri were activated by two configurations of signals(P<0.001).The FF signal induced activation in the bilateral inferior and middle frontal gyri(P<0.001).The right middle frontal gyrus activated by FF was significantly different from that by NF(P<0.006).The inferior and middle frontal gyri activated by two signals showed clear right sided laterality.Conclusion Some brain regions activated by two signals overlapped,but the activation patterns induced by two signals differed.The regions activated by NF were concentrated,which was assumably related to the familiarity of the unfiltered signals in the first language.The bilateral superior and middle temporal gyri were related to speech reception,phonological coding,and comprehension.Prosodic and linguistic signals were inseparable so that the bilateral inferior and middle frontal gyri got involved in the phonological and semantic processing of the FF signal,meanwhile,the right middle frontal gyrus played a key role in prosodic processing.In sum,the regions for language processing function in the form of a complex and holistic network as other functional areas of the brain.