Mechanisms Underlying the Control of Reflexive Orienting in Human Memory

我们都有过这样的时刻，一个物体或事件让我们想起了一种我们宁愿不去想的经历。当这种情况发生时，人们通常会试图将不愉快的记忆排除在意识之外。不幸的是，这些控制记忆的努力是在一次创伤经历之后无处不在的。然而，人们的记忆控制能力存在很大的变异性。有些人可以从意识中避免不必要的提醒，而另一些不太幸运的人则长期受到这些记忆的干扰，削弱了他们在创伤后的应对能力。是什么让一些人的注意力如此持久地被侵入性的提醒所吸引？回答这个问题需要我们了解注意力本身的性质，特别是将注意力定向到记忆中的认知和神经系统的性质。在国家科学基金会的支持下，俄勒冈大学的迈克尔·安德森将在大量关于视觉注意的认知和神经生物学研究的基础上，研究将注意力集中在记忆上的机制。这项先前的工作表明，有两种力量决定了注意力在视觉世界中的位置：一种是我们故意将注意力集中在空间中特定区域的内部机制，另一种是捕捉注意力并将其定向到突然出现的刺激的反射机制。这个项目考察了将注意力转移到视觉世界中突然开始的刺激上的神经系统是否也将注意力定向到不想要的记忆上。海马体的作用将有助于区分记忆引导的注意力和视觉引导的注意力。这个项目还将研究对记忆中反射性注意力转移的有意控制是否通过前额叶皮质调节的抑制机制来完成，该机制抑制海马体中的记忆，以及反射性定向系统本身。这项研究结合了传统的认知方法，一种测量介入式记忆的新方法，以及功能磁共振成像(FMRI)，以了解助记反射定向的神经认知基础及其抑制对其的调节。如果这一观点是正确的，那么这一观点将在注意力研究和长期记忆之间建立起高度具体的联系，并将为理解人类如何控制不想要的记忆提供一个丰富的框架。这些见解不仅具有理论意义，而且对改善那些遭受侵入性记忆折磨的人的状况具有深远的实践意义。对于许多经历大小创伤(如卡特里娜飓风)的人来说，不幸的是，控制不想要的记忆的必要性再清楚不过了。指定记忆控制的认知和神经生物学机制的基础研究将为以思维控制障碍为特征的临床症状理论提供信息，如创伤后应激障碍(侵入性闪回)、抑郁(不想要的沉思)、注意力缺陷/多动障碍(注意力分散)、强迫症(强迫症)和成瘾(渴望相关想法)。

We have all had moments when an object or event reminds us of an experience we would prefer not to think about. When this happens, people often attempt to exclude the unpleasant memory from awareness. These efforts to control memory are an unfortunately ubiquitous occurrence after a traumatic experience. However, there is great variability in people's memory control ability. Whereas some can keep unwanted reminders from awareness, other less fortunate individuals suffer chronic distraction from these memories, undermining their ability to cope in the aftermath of trauma. What causes some people's attention to be captured so persistently by intrusive remindings? Answering this question requires that we understand the nature of attention itself, and, in particular, the nature of the cognitive and neural systems that orient attention to memories. With support from the National Science Foundation, Michael Anderson at the University of Oregon will examine the mechanisms that focus attention on memories, building on a wealth of cognitive and neurobiological research on visual attention. This prior work shows that there are two forces that determine where attention is in the visual world: internal mechanisms by which we intentionally focus on a particular region in space, and reflexive mechanisms that capture attention and orient it to suddenly appearing stimuli. This project examines whether the neural systems that shift attention to stimuli with abrupt onsets in the visual world are also engaged to orient attention to an unwanted memory. The role of the hippocampus will help distinguish attention guided by memory from that guided by vision. This project will also examine whether intentional control over reflexive shifts of attention in memory is accomplished by inhibitory mechanisms mediated by the prefrontal cortex that suppress memories in the hippocampus, and the reflexive orienting system itself. The research combines traditional cognitive methods, a new approach to measuring intrusive memories, and functional magnetic resonance imaging (fMRI) to understand the neurocognitive basis of mnemonic reflexive orienting and its regulation by inhibition. If correct, this view will forge a highly specific connection between research on attention and long-term memory, and will specify a rich framework in which to understand how human beings control unwanted memories. Such insights are not merely of theoretical significance, but of profound practical importance in ameliorating the conditions of those suffering from intrusive memories. For numerous people experiencing traumas large (e.g. Hurricane Katrina) and small, the need to control unwanted memories is unfortunately all too clear. Basic research specifying the cognitive and neurobiological mechanisms of memory control will inform theories of clinical syndromes characterized by disordered thought control such as post-traumatic stress disorder (intrusive flashbacks), depression (unwanted ruminations), attention deficit / hyperactivity disorder (distractability), obsessive compulsive disorder (obsessive thoughts) and addiction (craving related thoughts).