【作者】 王海宝；

【导师】 张达人；

【作者基本信息】 中国科学技术大学 ， 生物物理， 2009， 博士

【摘要】 情绪性唤醒事件的记忆往往较其它中性事件持久而生动,这种效应被称为“情绪性记忆增强效应(emotional enhancement of memory,EEM)”。情绪记忆中性别差异是一个新的关注焦点。情绪记忆增强效应相关的杏仁核功能性别偏侧化(女左男右效应)是否存在时间依赖性,有待进一步研究。本研究采用fMRI和行为学相结合进行多时间点研究,以探讨杏仁核参与情绪记忆的短时阶段(20min)和长时阶段(24h)EEM机制是否分离或时间依赖的,进一步探讨情绪记忆增强效应中杏仁核功能的性别偏侧化是时间依赖的。本研究及既往研究结果分析表明,杏仁核的性别偏侧化发生于较长延迟时间(2～3w后),而在相对较短延迟时间(1w、24h,甚至30min以内)未有发现这种效应。因此,情绪记忆中性别效应可能存在时间依赖性。本研究显示:20min情绪记忆增强效应与右侧杏仁核相关,而24h情绪记忆增强效应与左侧杏仁核相关。本研究进一步确认和扩展了情绪记忆中杏仁核存在偏侧化和时间依赖性分离的观点(相关研究结果已发表在SCI期刊2009年“Neurobiology of Learning and Memory”)。既往研究显示:认知和情绪加工中存在持续效应和瞬时效应,采用事件相关-组块混合设计fMRI方法可同时检测记忆编码加工中的持续效应和瞬时效应。到目前为止,尚没有运用此方法进行情绪记忆研究的相关报道。行为学显示,老年人相对于年轻人存在年龄相关差异,具体机制尚不清楚。我们通过事件相关/组块混合设计fMRI方法,对相关脑区(主要包括内侧颞叶和前额叶)激活情况进行检测,研究老年人和年轻人杏仁核在情绪记忆持续效应与瞬时效应中的作用,以探讨老年人和年轻人情绪记忆机制的相对差异。本研究结果显示:老年人记忆能力较年轻人普遍下降,但情绪记忆增强效应仍然存在,且显示相对“正性情绪偏向”。不论年轻人和老年人,恐惧情绪记忆持续性效应与右侧杏仁核相关,瞬时效应与左侧杏仁核相关。持续效应和瞬时效应在年轻人和老年人情绪记忆中发挥不同的作用,年轻人情绪增强效应主要取决于持续效应,而相对年轻人而言,老年人内侧颞叶持续性作用有所下降,老年人情绪增强效应中瞬时效应起着主要作用。更多还原

【Abstract】 It is easier to remember emotionally arousing events than it is to recall those that are neutral.This phenomenon is known as the emotional enhancement of memory(EEM).A new focus in the field of emotional memory is the study of sex-related differences.Whether the sex-related lateralization of amygdala function (i.e.,the female-left/male-right effect) in the emotional enhancement of memory (EEM) is time-dependent remains unclear.To evaluate this phenomenon,we conducted a two time-point study(20 min vs.24 hr) using fMRI and behavioral paradigms.Analyses of the present and previous studies indicate that sex-related lateralization of amygdala function occurs in the 2- to 3-week EEM,but it does not occur in the 1-week,24-hr,or less than 30-min EEM,suggesting that this effect on emotional memory may be time-dependent.We found that the right amygdala predicted 20-min EEM,while the left amygdala predicted 24-hr EEM.Our results further confirm and extend the idea that the amygdala exhibits a lateralized and time-dependent dissociation.Generally transient and sustained effects exist in cognitive and emotional processes.Recent study with fMRI indicated that a combined design of event-related with blocked design could investigate the sustained and transient effect in the encoding process for memory simultaneously.By now,there have no report about the study on emotion memory by means of this design.Moreover, there is positive emotion bias behaviorally in the old.The mechanism of age-related difference is still unclear.The purpose of this study is to investigate the sustained and transient effect of emotion memory in the young and old,and the differences between the young and the old.Our results indicated that the memory ability declined in the old,but there still exists emotional enhancement effect and relative positive bias.The right amygdala is related to sustained effect of fear on EEM,while the left amygdala is correlated with transient effect in either young or old.Sustained and transient effect play different role in the emotional memory of the young and the old.More emotional enhancement effect mainly depends on sustained effect in the young.Corresponding to the young,sustained function of medial temporal lobe reduces in the old and the transient effect mainly play more important role in emotional enhancement effect for the old.更多还原