中文摘要：

情绪反应习惯化对个体的生存和适应具有重要的作用.为了研究大脑对不同情绪强度的正性和负性刺激的情绪习惯化,本研究设计2个实验条件,对极端正性（HP）、中等正性（MP）和中性图片以及极端负性（HN）、中等负性（MN）和中性图片的事件相关电位进行记录.使用双选择oddball范式,要求被试按不同的键做标准刺激和偏差刺激的分类任务.结果显示,重复呈现图片时,被试对HP刺激的唤醒度评定显著降低;在正性条件下,当重复呈现情绪刺激时N1潜伏期缩短;HP和MP刺激诱发的P3波幅随正性刺激的重复呈现显著降低,且下降的程度相似.与此相反,负性条件下,在上述所有指标上均未观察到显著的情绪习惯化效应.这提示,在自动化加工阶段和受控加工阶段,无论强度如何,正性刺激诱发的情绪反应都出现了显著的习惯化效应,而各种强度的负性刺激诱发的情绪反应均未出现习惯化效应;刺激的情绪强度对该习惯化效应无显著影响.

英文摘要：

The emotional habituation plays an important role in individuals＇ adaptation to the environment. The present study explored the brain＇s emotional habituation to positive and negative pictures of diverse emotional intensities. Event-related potentials（ERPs） were recorded in two different experimental sessions,for highly positive（HP）,mildly positive（MP） and neutral picture and for highly negative（HN）,mildly negative（MN） and neutral picture. Subjects were asked to perform a standard/deviant categorization task,irrespective of emotionality of the deviants. The behavior results showed that the arousal ratings for HP stimuli decreased significantly with stimulus repetition. In addition,the ERP results displayed earlier N1 peak latencies with stimulus repetition in the positive session. Furthermore,the size of the emotion effect,which was computed by the emotion-neutral differences,decreased significantly for HP and MP stimuli with stimulus repetition in P3 amplitudes. Conversely,the current study failed to observe an emotional habituation effect to negative stimuli in any behavioral or ERP indexes. These results suggest that the humans＇ emotional reactions to positive stimuli,irrespective of the emotional intensity,are susceptible to habituation,irrespective of information processing stage. However,the humans＇ emotional reactions to negative stimuli are resistant to habituation,irrespective of the emotional intensities of the stimuli and the information processing stage. This valence-specific habituation effect is independent of the emotional intensity of the stimuli.