Korean J Radiol.  2000 Mar;1(1):19-24. 10.3348/kjr.2000.1.1.19.

Functional MR Imaging of Working Memory in the Human Brain

• Na DG
• Ryu JW
• Byun HS
• Choi DS
• Lee EJ
• Chung WI
• Cho JM
• Han BK

• KMID: 1777291
• DOI: http://doi.org/10.3348/kjr.2000.1.1.19

Abstract

OBJECTIVE
In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. MATERIALS AND METHODS: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. RESULTS: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. CONCLUSION: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

Keyword

Brain, MR; Brain, function

MeSH Terms

Adult
Brain/*anatomy & histology/physiology
Echo-Planar Imaging
Female
Human
*Magnetic Resonance Imaging
Male
Memory/*physiology
Photic Stimulation
Support, Non-U.S. Gov't

Figure

• 

  Fig. 1 Functional MR imaging of a healthy 26-year-old male obtained during verbal (A-C) and visual working memory tasks (D-F). A-C. Activation map images obtained during verbal working memory task. Map image of the upper level of the brain (A) demonstrates bilateral activated signals in the premotor area (BA 6)(long arrows), supramarginal gyrus (BA 40)(short arrows), and superior parietal cortex (BA 7)(arrow heads). The activated signals are stronger in the left premotor and superior parietal cortex than in the right hemisphere. An activated signal is also seen in the right prefrontal cortex (BA 9)(curved arrow) and anterior cingulate gyrus (BA 24). Map image of the middle level of the brain (B) shows activated signals in the left inferior frontal lobe (BA 44, 45)(long arrow), left superior temporal gyrus (BA 22)(short arrow), middle temporal gyrus (BA 21)(thick short arrows), and prefrontal cortex(BA 10)(curved arrow). Map image of the lower level of the brain (C) shows activated signals in the right and left lateral occipital cortices(BA 18,19) and posterior fusiform gyrus (BA 37)(arrows). Small activated signals are also seen in the left insula and middle temporal gyrus. D-F. Activation map images obtained during visual working memory task. Map image of the upper level of the brain (D) shows neither activated signals in the supramarginal gyrus nor lateralization of activated signals in the frontal and parietal lobes. Map image of the middle level of the brain (E) shows no activated signals in the left inferior frontal or temporal gyrus. An activated signal (arrow) in the prefrontal cortex corresponds to the signal activated during the verbal working memory task (D, E). Map image of the lower level of the brain(F) shows bilateral activated signals similar to those seen during the verbal working memory task in the right and left occipital cortices and posterior fusiform gyri.

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