情绪记忆增强效应的时间依赖性

探讨情绪记忆短时和长时增强效应相对特异性机制以及唤醒度和效价在情绪记忆中的作用。运用不同阶段提取和不同情绪类别相结合的多因素设计方法, 对20位正常年轻成人进行行为学检测。结果显示, 情绪对记忆加工不同阶段(短时和长时)的调节作用(增强效应)具有时间依赖性, 且主要取决于情绪唤醒度, 而无显著正负效价性差异。在短时阶段主要涉及高唤醒度的增强; 而长时阶段涉及不同水平唤醒度的增强, 不同唤醒度的增强效应存在相对分离。

Time Dependence of Enhancement Effects in Emotional Memory

Extensive evidence from human and animal studies indicates that emotionally arousing events are more likely to be remembered than neutral events. This phenomenon is known as the emotional enhancement of memory (EEM) and is attributed to emotional modulation either of different memory stages, including encoding and consolidation, or memory phases, including short- and long-term memory. Current theories on emotional memory suggest that EEM effects occur via modulation of the amygdala and other related cerebral regions,including the hippocampus and prefrontal cortex. In light of the time dependence of consolidation observed in animal studies, it is necessary to conduct an integrative investigation of both the time-dependent effects of emotional memory and the effects of emotional arousal and valence on human memory.A multifactorial experimental design of 2×4 (times×picture categories) was used. Experiments comprised encoding and recognition sessions. Each subject (n=20) completed one encoding phase and two recognition phases, one after 20 min to measure short-term recognition (R 1) and one after 24 h for long-term recognition (R2). During encoding, subjects were required to rate the picture on a three-point emotional intensity scale (1=low, 2=medium, 3=high) and to remember the picture. During R1 and R2, 320 pictures were presented, half of which had been presented during encoding and the other half had never seen by the subject. Subjects were instructed to indicate whether each picture was "old" or "new" by pressing a key. Behavioral data were analyzedusing SPSS 10.0 software.The arousal level was highest for fear, moderate for happiness and sadness, and lowest for neutral feelings.EEM effects were correlated with the highest arousal for short-term memory (Pr: F(3,76)=7.50, P<0.001; d':F(3,76)=7.76, P<0.001) and with arousal levels, but not valence, for long-term memory (Pr: F(3,76)=32.76,P<0.001, d': F(3,76)=29.86, P<0.001). Moreover, dissociation of EEM effects was observed between different arousal levels and time courses. Interactions between times (R1 and R2) and groups (fear, happiness, sadness and neutral) were significant (Pr: F(3,152)=6.89, p<0.001).The results confirm that emotional modulation of different stages of memory is time-dependent and that time-dependent EEM effects are predominantly associated with arousal levels, but not emotional valence.Moreover, dissociation of EEM effects between different arousal levels and time courses was observed.