Smith E E, Jonides J, Koeppe R A
University of Michigan, Ann Arbor 48103, USA.
Cereb Cortex. 1996 Jan-Feb;6(1):11-20. doi: 10.1093/cercor/6.1.11.
Three experiments used position emission tomography (PET) to study the neural basis of human working memory. These studies ask whether different neural circuits underly verbal and spatial memory. In Experiment 1, subjects had to retain for 3 sec. either the names of four letters (verbal memory) or the positions of three dots (spatial memory). The PET results manifested a clear cut double dissociation, as the verbal task activated primarily left-hemisphere regions whereas the spatial task activated only right-hemisphere regions. In Experiment 2, the identical sequence of letters was presented in all conditions, and what varied was whether subjects had to remember the names of the letters (verbal memory) or their positions in the display (spatial memory). In the verbal task, activation was concentrated more in the left than the right hemisphere; in the spatial task, there was substantial activation in both hemispheres, though in key regions, there was more activation in the right than the left hemisphere. Experiment 3 studied only verbal memory, and showed that a continuous memory task activated the same regions as the discrete verbal task used in Experiment 1. Taken together, these results indicate that verbal and spatial working memory are implemented by different neural structures.
三项实验利用正电子发射断层扫描（PET）技术来研究人类工作记忆的神经基础。这些研究探讨了不同的神经回路是否构成言语记忆和空间记忆的基础。在实验1中，受试者必须将四个字母的名称（言语记忆）或三个点的位置（空间记忆）保持3秒钟。PET结果显示出明显的双重分离，因为言语任务主要激活左半球区域，而空间任务仅激活右半球区域。在实验2中，所有条件下呈现的字母序列相同，不同的是受试者是必须记住字母的名称（言语记忆）还是它们在显示屏中的位置（空间记忆）。在言语任务中，激活更多地集中在左半球而非右半球；在空间任务中，两个半球均有大量激活，不过在关键区域，右半球的激活比左半球更多。实验3仅研究言语记忆，结果表明连续记忆任务激活的区域与实验1中使用的离散言语任务激活的区域相同。综合来看，这些结果表明言语工作记忆和空间工作记忆是由不同的神经结构实现的。
