厌恶情绪加工特点的事件相关电位研究

An ERP Study of Disgust Processing

厌恶作为一种威胁相关情绪有着帮助人们躲避有害刺激的进化意义。近年来的研究表明,厌恶加工能拥有独特的神经机制,主要表现为在感觉刺激输入早期起抑制作用。本研究使用高时间分辨率的事件相关电位技术(event-related potential,ERP)作为研究手段,探究正常被试观看厌恶图片时脑电活动变化。采用视觉搜索范式作为实验任务,考察不同加工阶段注意资源消耗特点。脑电结果表明,厌恶加工确实存在独特的加工机制,表现为皮层活动先抑制后增强。行为结果呈显著交互作用:情绪图呈现时间较短时(0/300 ms),被试任务表现受负性情绪加工干扰;情绪图呈现时间较长时(600/900 ms),被试任务表现不受负性情绪干扰。研究结果支持负性情绪两阶段加工模型,即厌恶加工也存在先自动化后控制化的两个阶段,并且在自动化加工完全消失之前存在两种加工进程并存的过度阶段。

As one kind of threat related emotions, disgust has the evolutional meaning to help human being avoid harmful stimulus. Recent studies have demonstrated the unique neural processing mechanism of disgust, which could be described as inhibiting sensory inputs at early stage of stimulus processing. In this study, the event-related potential（ERP） technique was employed with its advantage in time resolution to learn about the neural processing when participants watching disgusting compared with neutral pictures. After watching emotional pictures presented in different lengths of time, participants were instructed to finish a visually search task in order to examine the consumptions of attentional resources under different conditions. EPR results revealed that the effect of disgust first began at 100 ms after picture onset with a suppressed waveform compared to the neutral condition while enhanced neural activity was detected at the follow-up stage of detailed processing. The behavior results showed significant interactions; the task performance was hampered by negative emotion processing when the stimulus length was shorter（0/300 ms）. In contrast, there was no behavioral difference between two emotional conditions when the stimulus length was longer（600/900 ms）. The current results suggest that disgust has unique neural processing mechanism which fits the tow-stage model of negative emotion processing. The results further indicate that there is transition phase existing in which both automatic processing and controlled processing activate simultaneously.