对一些恐惧事情的预先猜测，在事情发生以后会加深对于这件事的记忆。如果一位老师正在同怯场做斗争，在每一次她上课之前她都会感觉焦虑；那么她花越多的时间担忧接下来的课，在课时结束之后关于焦虑的记忆就会越强烈。不幸的是，她陷入了情绪的恶性循环，因为她关于焦虑的记忆越强烈，她就会变得越为她的行为焦虑。也许，这种不愉快的推测，唤醒了大脑中的“恐怖回路”，进而强化了记忆。-psytopic.com
长久以来，心理学家们都知道，遭遇暴力事件或者自己所钟爱人的突然去逝等负性情绪事件会比普通的日常生活事件在脑海里留下更为清晰深刻的印象。
为深入研究这类记忆是如何形成的，威斯康星麦迪逊大学的研究者们发现，即使是在事件发生以前，对恐惧情境的预期也可以激活大脑的两个记忆形成区域。
这就意味着简单的预期在痛苦记忆的清晰程度方面起着令人意想不到的作用。
这个大脑成像的研究发现，已经发表于本期的国家科学院学报，这对治疗创伤应激(PTSD)和社交恐惧等心理疾病有重大的影响，这类疾病特征是经常有恐惧事件的记忆闪回或者插入。
科罗拉多大学研究生，研究的第一作者Kristen Mackiewicz说，“本研究的主要动机是为临床应用，了解运用关于记忆的知识。为此，我们可以更好的治疗创伤应激(PTSD)类似的有大量记忆成分的障碍。”Kristen Mackiewicz在麦迪逊大学做学生时就已经在做关于预期的研究了。
此项研究也建立在研究期望在情绪以及临床疾病中的作用的相关新研究之上 ，UW-Madison的生理以及心理学副教授，资深学者Jack Nitschke说。
“我们的研究同时阐明预期延展记忆信息的能力如何。”实验合作者，UW-Madison的威斯曼(Waisman)大脑成像和行为实验室人员Nitschke说。“对一些恐惧的事情的预期，在事情发生以后会加深对于此事的记忆。”
比如，一个老师正在同怯场做斗争，在每一次她上课之前她都会感觉焦虑。UW-Madison研究揭示，她花越多的时间来担忧接下来的课，课结束之后关于焦虑的记忆就会越强烈。不幸的是，她陷入了情绪的恶性循环，因为她关于焦虑的记忆越强烈，她就会变得越为她的行为焦虑。
UW-Madison科学家们发现，当人在预期一个困难情境时，大脑的两个关键区域杏仁核和海马回就变得活跃。科学家们认为杏仁核与情绪记忆的信息有关，海马回帮助大脑形成长时记忆。Nitschke说。
研究者们采用了核磁共振成像技术研究了36名健康志愿者的大脑活动，核磁共振成像技术能够对人体组织进行高对比度的成像。他们给被试两种类型的信号，一个是中性的，另一个是一些令人恐惧的图片，如清晰血腥的图片、腐败的人体。在给被试呈现了许多这些暴力图片之后30分钟，通过询问，测定被试在多大程度上能够对刚才看见的图片进行回忆。
“我们发现，对图片做预期期间杏仁核和海马回越活跃，就越可能正确的回忆图片。”Nitschke说。
实验两星期后，科学家们再次找到被试，测量他们能够在多大程度上回忆实验中的图片。这一次，他们发现，两星期前训练观察图片时杏仁核和海马回越活跃的被试，回忆图片的成绩就越好。这表示被试的大脑已经开始把关于图片的短时记忆向长时记忆转变。
Mackiewicz说，对不悦情境的预期很可能启动了大脑中的“恐怖回路或者唤醒”，这“恐怖回路或唤醒”帮助强化这些陈旧的记忆。
“将来，我们会寻找降低病人唤醒反应的方法，让他们不容易唤起负性记忆。”
威斯曼(Waisman)大脑成像及行为实验室的科学家Issidoros Sarinopoulos和Krystal Cleven对此项研究也有贡献。
附原文：
Anticipation Plays A Powerful Role In Human Memory, Brain Study Finds
Psychologists have long known that memories of disturbing emotional events - such as an act of violence or the unexpected death of a loved one - are more vivid and deeply imprinted in the brain than mundane recollections of everyday matters.
Probing deeper into how such memories form, researchers at the University of Wisconsin-Madison have found that the mere anticipation of a fearful situation can fire up two memory-forming regions of the brain - even before the event has occurred.
That means the simple act of anticipation may play a surprisingly important role in how fresh the memory of a tough experience remains.
The findings of the brain-imaging study, which appear in the current issue of the Proceedings of the National Academy of Sciences, have important implications for the treatment of psychological conditions such as post-traumatic stress disorder (PTSD) and social anxiety, which are often characterized by flashbacks and intrusive memories of upsetting events.
"The main motivation for this study was a clinical one, in terms of understanding and applying knowledge about memory so that we can better inform the treatment of disorders that have a large memory component, like PTSD," says lead author Kristen Mackiewicz, a graduate student at the University of Colorado who worked on the anticipation study while a student at UW-Madison.
The project also builds on a relatively new body of work on the role of anticipation in emotion and clinical disorders, says senior author Jack Nitschke, a UW-Madison assistant professor of psychiatry and psychology.
"Our study illustrates how the power of expectancy can extend to memory formation as well," says Nitschke, also an associate of UW-Madison's Waisman Laboratory for Brain Imaging and Behavior. "Just the expectation of seeing something bad can enhance the memory of it after it happens."
A teacher who struggles with stage fright, for example, might feel anxious before every class she has to teach. The UW-Madison work suggests that the longer she spends dreading her next lecture, the stronger her memory of the uncomfortable experience is likely to be when it is over. Unfortunately, that sets a vicious cycle in motion, because the stronger her memory of discomfort, the worse her performance anxiety is likely to get.
The UW-Madison scientists found that two key regions of the brain - the amygdala and the hippocampus - become activated when a person is anticipating a difficult situation. Scientists think the amygdala is associated with the formation of emotional memories, while the hippocampus helps the brain form long-term recollections, Nitschke says.
The researchers studied the brain activity of 36 healthy volunteers using a technique known as functional magnetic resonance imaging, which produces high-contrast images of human tissue. They began by showing the volunteers two kinds of signals. One was neutral, but the other indicated that some type of gruesome picture was soon to follow, such as explicit photos of bloody, mutilated bodies. Thirty minutes after the researchers had shown dozens of violent images, they quizzed study participants on how well they remembered the pictures they had just seen.
"We found that the more activated the amygdala and hippocampus had been during the anticipation [of the pictures], the more likely it was that a person would remember more of them right away," says Nitschke.
Two weeks after the experiment, scientists met with the study subjects again to measure how well they remembered the same disturbing images. This time, they found that people who best remembered them had shown the greatest amygdala and hippocampus activity during the picture-viewing exercise two weeks before. That suggested that those subjects' brains had already started converting short-term memories of the images into longer-lasting ones.
Mackiewicz says the anticipation of an uncomfortable situation probably kick-starts a kind of "arousal or fear circuitry" in the brain, which in turn helps to reinforce old memories.
"In the future, we could look for ways to dampen that arousal response in patients so that they do not evoke negative memories so easily," she adds.
Scientists Issidoros Sarinopoulos and Krystal Cleven at the Waisman Laboratory for Brain Imaging and Behavior also contributed to the study.
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