Neural Mechanisms of Short-Term Memory

复杂的任务通常需要同时记住几个想法。例如，在进行心理加法时，我们必须在应用更新这些数字的操作时在脑海中同时处理几个数字。众所周知，在任何给定的时间内，我们能记住的信息量是有明显限制的，而这些限制与我们的推理和理解能力——简而言之，与我们的智力——有着密切的关系。然而，造成这些容量限制的短期记忆系统的基本结构仍不清楚。最近的心理学研究表明，大脑中最重要的一条信息、大脑中保存的其他信息，但目前不是注意力的焦点，以及大脑中没有保存但在长期记忆中可用的信息，是可以区分的。这个项目的目标是了解负责表示这些不同信息状态的大脑机制。在美国国家科学基金会的支持下，密歇根大学的约翰·乔尼德斯博士和他的同事们将利用功能性磁共振成像技术研究短期记忆的结构。这项研究将检验志愿者在短期记忆的各种假定状态下保留、检索和更新信息时的神经反应。除了提供大脑功能定位的传统方法外，该研究还将采用分析来检查大脑激活的功能网络，从而阐明实现短期记忆的大脑机制。这项工作还将检查对不同类型信息的神经反应，如口头、空间和图像信息，并检查与每种形式的短期记忆有关的大脑网络。由于人类的智力很大程度上依赖于短期记忆的容量限制，了解大脑如何实现短期记忆可能对整个认知产生重大影响。这项研究进一步的理解可能会为旨在提高短期记忆能力和智力的方法提供信息。本研究项目也将为参与本研究的本科生和研究生提供功能磁共振成像技术的综合训练。这项研究的结果将通过出版物和研讨会广泛传播。

Complex tasks frequently require holding in mind several ideas at once. For example, when performing mental addition we must juggle several numbers in mind while applying operations to update those numbers. It is well-established that there are distinct limits to the amount of information that can be held in mind at any given time and that these limits have a close relationship to our abilities to reason and to comprehend -- in short, to our intelligence. However, the fundamental architecture of the short-term memory system responsible for these capacity limits remains unclear. Recent psychological research suggests that distinctions can be drawn between a single piece of information at the forefront of the mind, other information that is being held in mind, but currently not the focus of attention, and information that is not being held in mind, but available in long-term memory. The goal of this project is to understand the brain mechanisms responsible for representing these different states of information. With support from the National Science Foundation, Dr. John Jonides and colleagues at the University of Michigan will investigate the architecture of short-term memory using functional magnetic resonance imaging. The research will examine neural responses as human volunteers retain, retrieve, and update information in the various putative states of short-term memory. In addition to traditional measures that afford brain localization of function, the research will employ analyses that examine functional networks of brain activation, thus elucidating brain mechanisms by which short-term memory is achieved. The work will also examine neural responses to different types of information, such as verbal, spatial, and pictorial information and examine the brain networks involved in subserving short-term memory of each form.Since much of human intelligence depends on capacity limits of short-term memory, understanding how the brain implements short-term memory could have substantial impact on cognition as a whole. The understanding furthered by this research may inform methods that aim to increase short-term memory capacity and intelligence. This research project will also provide comprehensive training functional magnetic resonance imaging techniques to undergraduate and graduate students involved in the project. Findings from this study will be disseminated widely through publications and a seminar.