Nee Derek Evan, Jonides John
Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1043, USA.
Proc Natl Acad Sci U S A. 2008 Sep 16;105(37):14228-33. doi: 10.1073/pnas.0802081105. Epub 2008 Aug 29.
Behavioral research has led to the view that items in short-term memory can be parsed into two categories: a single item in the focus of attention that is available for immediate cognitive processing and a small set of other items that are in a heightened state of activation but require retrieval for further use. We examined this distinction by using an item-recognition task. The results show that the item in the focus of attention is represented by increased activation in inferior temporal representational cortices relative to other information in short-term memory. Functional connectivity analyses suggest that activation of these inferior temporal regions is maintained via frontal- and posterior-parietal contributions. By contrast, other items in short-term memory demand retrieval mechanisms that are represented by increased activation in the medial temporal lobe and left mid-ventrolateral prefrontal cortex. These results show that there are two distinctly different sorts of access to information in short-term memory, and that access by retrieval operations makes use of neural machinery similar to that used in long-term memory retrieval.
行为研究得出了这样一种观点，即短期记忆中的项目可分为两类：处于注意力焦点的单个项目，可用于即时认知处理；以及一小部分其他项目，它们处于增强的激活状态，但需要检索才能进一步使用。我们通过使用项目识别任务来检验这种区别。结果表明，相对于短期记忆中的其他信息，注意力焦点中的项目在下颞叶表征皮层中表现为激活增加。功能连接分析表明，这些下颞叶区域的激活通过额叶和顶叶后部的作用得以维持。相比之下，短期记忆中的其他项目需要检索机制，这表现为内侧颞叶和左中腹外侧前额叶皮层的激活增加。这些结果表明，在短期记忆中有两种截然不同的信息获取方式，并且通过检索操作进行的获取利用了与长期记忆检索中使用的神经机制相似的神经机制。
