音调与语音Oddball实验的脑电流源模型分析

Brain Electrical Source Analysis during Tonal and Phonetic Oddball Paradigms

采用语音和音调Oddball实验范式,研究大脑离散电流源在靶刺激响应过程中的电流时间过程。采集了健康受试者的64导联脑电数据,建立并比较音调和语音靶刺激ERPs数据的区域源电流模型。结果显示:听觉靶刺激识别的主要神经源包括双侧颞上回和双侧脑岛。音调靶刺激识别引起右侧区域源的N2/P3幅度大于左侧,呈现右偏侧化,其中脑岛的右偏侧化较明显,而语音靶刺激识别引起左侧区域源N2/P3幅度大于右侧,呈现左偏侧化,双侧脑岛和双侧颞上回都出现明显的左偏侧化。研究表明:靶刺激识别这一脑处理过程随刺激模式的不同存在差异,音调靶刺激识别以右侧脑岛和右侧颞上回的激活更强,而语音靶刺激识别以左侧颞上回的激活更强。

In this paper,time courses of discrete cortical current sources evoked by target stimuli were investigated with tonal and phonetic oddball paradigms.64-channel ERPs were recorded in healthy subjects during the paradigms.A regional source model was then introduced to ERPs data in response to tonal and phonetic target stimuli.Activities of regional sources indicated bilateral superior temporal gyri and bilateral insula were sources involved in auditory target detection.While tonal and phonetic task were compared,tonal target detection produced right-greater-than-left hemispheric asymmetry of N2/P3 amplitude in bilateral source activities and the asymmetry more obviously occurred in bilateral insula,and on the contrary,phonetic target detection produced left-greater-than-right hemispheric asymmetry of N2/P3 amplitude in bilateral source activities and the asymmetry obviously occurred in bilateral superior temporal gyri and insula.It was indicated that target processing was modality-specific,tonal target detection produced stronger activation of right insula and right superior temporal gyrus,while phonetic target processing involved stronger activations of left superior temporal gyrus.