Salvia Emilie, Bestelmeyer Patricia E G, Kotz Sonja A, Rousselet Guillaume A, Pernet Cyril R, Gross Joachim, Belin Pascal
Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow Glasgow, UK.
Bangor Imaging Unit, School of Psychology, Bangor University Gwynedd, UK.
Front Neurosci. 2014 Dec 22;8:422. doi: 10.3389/fnins.2014.00422. eCollection 2014.
Magneto-encephalography (MEG) was used to examine the cerebral response to affective non-verbal vocalizations (ANVs) at the single-subject level. Stimuli consisted of non-verbal affect bursts from the Montreal Affective Voices morphed to parametrically vary acoustical structure and perceived emotional properties. Scalp magnetic fields were recorded in three participants while they performed a 3-alternative forced choice emotion categorization task (Anger, Fear, Pleasure). Each participant performed more than 6000 trials to allow single-subject level statistical analyses using a new toolbox which implements the general linear model (GLM) on stimulus-specific responses (LIMO-EEG). For each participant we estimated "simple" models [including just one affective regressor (Arousal or Valence)] as well as "combined" models (including acoustical regressors). Results from the "simple" models revealed in every participant the significant early effects (as early as ~100 ms after onset) of Valence and Arousal already reported at the group-level in previous work. However, the "combined" models showed that few effects of Arousal remained after removing the acoustically-explained variance, whereas significant effects of Valence remained especially at late stages. This study demonstrates (i) that single-subject analyses replicate the results observed at early stages by group-level studies and (ii) the feasibility of GLM-based analysis of MEG data. It also suggests that early modulation of MEG amplitude by affective stimuli partly reflects their acoustical properties.
采用脑磁图（MEG）在单受试者水平上检测大脑对情感性非言语发声（ANV）的反应。刺激由蒙特利尔情感语音中的非言语情感爆发组成，这些爆发经过变形以参数方式改变声学结构和感知到的情感属性。在三名参与者执行三选一强制选择情绪分类任务（愤怒、恐惧、愉悦）时记录头皮磁场。每个参与者进行了超过6000次试验，以便使用一个新的工具箱在单受试者水平上进行统计分析，该工具箱在特定刺激反应上实现了通用线性模型（GLM）（LIMO-EEG）。对于每个参与者，我们估计了“简单”模型[仅包括一个情感回归变量（唤醒或效价）]以及“组合”模型（包括声学回归变量）。“简单”模型的结果显示，在每个参与者中都出现了先前在群体水平研究中已经报道的效价和唤醒的显著早期效应（最早在刺激开始后约100毫秒）。然而，“组合”模型表明，在去除声学解释的方差后，唤醒的效应所剩无几，而效价的显著效应仍然存在，尤其是在后期阶段。这项研究表明：（i）单受试者分析重复了群体水平研究在早期阶段观察到的结果；（ii）基于GLM分析MEG数据的可行性。它还表明，情感刺激对MEG振幅的早期调制部分反映了它们的声学特性。
