Fiez J A, Raife E A, Balota D A, Schwarz J P, Raichle M E, Petersen S E
Department of Neurology and Neurological Surgery, McDonnell Center for Higher Brain Function, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
J Neurosci. 1996 Jan 15;16(2):808-22. doi: 10.1523/JNEUROSCI.16-02-00808.1996.
Positron emission tomography (PET) was used to investigate the functional brain anatomy associated with the short-term maintenance of linguistic information. Subjects were asked to retain five related words, unrelated words, or pseudowords silently for the duration of a 40 sec PET scan. When brain activity during these short-term maintenance tasks was compared with a visual fixation control task, increases were found bilaterally in the dorsolateral prefrontal cortex and cerebellum, and medially in the supplementary motor area. Furthermore, effects of stimulus condition and recall performance were found in the left frontal operculum. To investigate the role of articulatory systems in the maintenance of verbal information, regional activation was compared across the maintenance tasks and a covert articulation task (silent counting). The cerebellum was active in both task conditions, whereas activation in prefrontal regions was specific to the maintenance condition. Conversely, greater activation was found in a left middle insular region in the silent counting than in the maintenance tasks. Based on converging results in this and previous studies, dorsolateral prefrontal cortical areas appear to contribute to the maintenance of both verbal and nonverbal information, whereas left frontal opercular regions appear to be involved specifically in the rehearsal of verbal material. Contrary to results found in other studies of working memory, activation was not found in the inferior parietal cortex, suggesting that this area is involved in aspects of stimulus encoding and retrieval, which were minimized in the present study.
正电子发射断层扫描（PET）被用于研究与语言信息短期维持相关的大脑功能解剖结构。在40秒的PET扫描期间，要求受试者默读记住五个相关单词、不相关单词或假词。当将这些短期维持任务期间的大脑活动与视觉注视控制任务进行比较时，发现双侧背外侧前额叶皮质和小脑以及内侧辅助运动区的活动增加。此外，在左侧额盖发现了刺激条件和回忆表现的影响。为了研究发音系统在言语信息维持中的作用，比较了维持任务和隐蔽发音任务（默读计数）期间的区域激活情况。在两种任务条件下小脑均有激活，而前额叶区域的激活则特定于维持条件。相反，与维持任务相比，默读计数时左侧岛叶中部区域的激活更强。基于本研究和先前研究的一致结果，背外侧前额叶皮质区域似乎有助于言语和非言语信息的维持，而左侧额盖区域似乎专门参与言语材料的复述。与其他工作记忆研究的结果相反，在顶下小叶未发现激活，这表明该区域参与刺激编码和检索，而在本研究中这些方面被最小化。
