Smith E E, Jonides J, Marshuetz C, Koeppe R A
Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1109, USA.
Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):876-82. doi: 10.1073/pnas.95.3.876.
We review research on the neural bases of verbal working memory, focusing on human neuroimaging studies. We first consider experiments that indicate that verbal working memory is composed of multiple components. One component involves the subvocal rehearsal of phonological information and is neurally implemented by left-hemisphere speech areas, including Broca's area, the premotor area, and the supplementary motor area. Other components of verbal working memory may be devoted to pure storage and to executive processing of the contents of memory. These studies rest on a subtraction logic, in which two tasks are imaged, differing only in that one task presumably has an extra process, and the difference image is taken to reflect that process. We then review studies that show that the previous results can be obtained with experimental methods other than subtraction. We focus on the method of parametric variation, in which a parameter that presumably reflects a single process is varied. In the last section, we consider the distinction between working memory tasks that require only storage of information vs. those that require that the stored items be processed in some way. These experiments provide some support for the hypothesis that, when a task requires processing the contents of working memory, the dorsolateral prefrontal cortex is disproportionately activated.
我们回顾了关于言语工作记忆神经基础的研究，重点关注人类神经影像学研究。我们首先考虑一些实验，这些实验表明言语工作记忆由多个成分组成。其中一个成分涉及语音信息的默读复述，在神经层面上由左半球言语区域实现，包括布洛卡区、运动前区和辅助运动区。言语工作记忆的其他成分可能专门用于纯粹的存储以及对记忆内容的执行加工。这些研究基于减法逻辑，即对两个任务进行成像，二者的区别仅在于一个任务可能有一个额外的过程，而差异图像被认为反映了该过程。然后我们回顾一些研究，这些研究表明可以用减法以外的实验方法得到先前的结果。我们重点关注参数变化法，即改变一个据推测反映单一过程的参数。在最后一部分，我们考虑只需要存储信息的工作记忆任务与需要以某种方式对存储项目进行加工的工作记忆任务之间的区别。这些实验为以下假设提供了一些支持：当一项任务需要处理工作记忆的内容时，背外侧前额叶皮层会有不成比例的激活。
