人类镜像系统参与音乐情绪的自动加工：来自EEG的证据

大脑中线电极诱发的μ抑制波(包括α和β频段)是人类镜像系统活动的电生理指标。尽管音乐情绪表现被认为是通过模仿个体的心理状态来实现的, 但是尚未有研究探讨人类镜像系统与音乐情绪加工的关系。本研究通过EEG技术, 采用跨通道情绪启动范式, 探究人类镜像系统是否参与和弦情绪的自动加工。愉悦或不愉悦的和弦启动情绪一致与不一致的目标面孔。行为结果显示, 被试对情绪一致面孔的反应显著快于情绪不一致面孔的反应。EEG结果显示, 在听觉刺激出现后的500~650 ms之间, 与情绪一致条件相比, 情绪不一致条件诱发了β频段的去同步化。在听觉刺激出现后的300~450 ms, 无论是情绪一致, 还是不一致条件, 都诱发了α频段的去同步化。源分析结果显示, μ抑制波主要出现在人类镜像系统的相关脑区。这些结果表明, 音乐情绪的自动加工与人类镜像系统的活动密切相关。

Role of the human mirror system in automatic processing of musical emotion: Evidence from EEG

The human mirror system (HMS) consists of a core parietofrontal network of regions in the inferior parietal lobule and inferior frontal gyrus/premotor cortex, which can be activated by action observation and execution. Mu rhythm suppression is considered an electrophysiological indicator of the HMS given their similarity in reaction to action observation and execution. Mu rhythm comprises α (8-13 Hz) and β (15-25 Hz) frequency bands, which are typically measured at the power change of midline electrode sites. The β frequency band is related to the movement preparation, whereas the α frequency band is suppressed during the execution of movement. Consistent with the role of the HMS in social cognition, such as emotion understanding, theory of mind, and empathy, mu rhythm suppression is modulated by the processing of social information, such as facial emotional information. Emotion is an important component of social communication. In addition to the emotional facial expression, music is an effective means of expressing emotions through imitation, and for most of people, the main purpose of listening to music is to process musical emotions. However, information on whether mu rhythm suppression is involved in the processing of musical emotions is limited. The aims of the present study were to examine whether mu rhythm suppression is modulated by the processing of musical emotions using Electroencephalogram (EEG). Given that the HMS is involved in the automatic processing of musical emotions, the present study focused on this point by using a cross-modal affective priming paradigm with an SOA of 200 ms. Fifteen musically untrained normal individuals participated in the experiment. Target faces with pleasant and unpleasant emotions were primed by affectively congruous or incongruous chords. Forty-eight congruous and 48 incongruous trials were included in the present study. The participants were instructed to decide as fast and accurately as possible whether the emotion of the face was pleasant or unpleasant. Behavioral results showed that the affectively congruous target faces (M = 575.17 ms, SD = 75.34) were judged faster than affectively incongruous target faces (M = 605.38 ms, SD = 87.74). However, no difference was observed in the percentages of correct responses to the affectively congruous (M = 98%, SD = 2.4%) and incongruous (M = 97%, SD = 2.5%) target faces. Electrophysiological results revealed that the β frequency band (18-24 Hz) oscillations were less strong for incongruous than for congruous target faces at a time window of 500-650 ms after the onset of chords. A significant desynchronization of the α frequency band was observed for both the congruous and incongruous target stimuli at a time window of 300-450 ms after the onset of chords. Moreover, source analysis exhibited the central-frontal area responsible for automatic musical emotion processing, where the HMS is located. Overall, the present study showed that mu rhythm suppression was involved in the automatic processing of chord emotions, as shown in the α and β frequency bands. The results extend the role of the mu rhythm and provide electrophysiological support for the role of the HMS in the processing of musical emotions.