Activation of human prefrontal cortex during spatial and nonspatial working memory tasks measured by functional MRI
Activation of human prefrontal cortex during spatial and nonspatial working memory tasks measured by functional MRI
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DOI：
10.1093/cercor/6.4.600
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发表时间：
1996-07-01
期刊：
影响因子：
3.7
通讯作者：
GoldmanRakic, P
中科院分区：
文献类型：
--
作者：
McCarthy, G;Puce, A;GoldmanRakic, P
在非人灵长类动物的前额叶皮层（PFC）中，已经发现了空间位置、物体、面孔和模式的独立工作记忆域。我们已经使用功能性磁共振成像检查是否空间和非空间视觉工作记忆过程中同样分离的人类PFC。主题进行任务，要求他们记住连续的视觉刺激的位置或形状。我们发现，工作记忆任务的记忆成分影响PFC激活的半球模式。空间（位置）工作记忆任务优先激活右半球的额中回（MFG），而非空间（形状）工作记忆任务激活两个半球的MFG。此外，在非空间形状任务中，左半球的激活区域延伸到额下回。知觉目标（DOT）检测任务也激活了MFG双边，但在大约一半的工作记忆任务的水平。MFG的激活发生在任务开始的3-6 s内，并在任务偏移后下降。时程分析显示，扣带回的激活发生在任务完成后，一个不同的模式。扣带回激活是最大的形状任务，并在左半球更大。目前的研究结果支持PFC的突出作用，特别是，MFG在工作记忆中，并表明，任务的记忆内容影响半球激活的相对权重。
Separate working memory domains for spatial location, and for objects, faces, and patterns, have been identified in the prefrontal cortex (PFC) of nonhuman primates. We have used functional magnetic resonance imaging to examine whether spatial and nonspatial visual working memory processes are similarly dissociable in human PFC. Subjects performed tasks which required them to remember either the location or shape of successive visual stimuli. We found that the mnemonic component of the working memory tasks affected the hemispheric pattern of PFC activation. The spatial (LOCATION) working memory task preferentially activated the middle frontal gyrus (MFG) in the right hemisphere, while the nonspatial (SHAPE) working memory task activated the MFG in both hemispheres. Furthermore, the area of activation in the left hemisphere extended into the inferior frontal gyrus for the nonspatial SHAPE task. A perceptual target (DOT) detection task also activated the MFG bilaterally, but at a level approximately half that of the working memory tasks. The activation in the MFG occurred within 3-6 s of task onset and declined following task offset. Time-course analysis revealed a different pattern for the cingulate gyrus, in which activation occurred upon task completion. Cingulate activation was greatest following the SHAPE task and was greater in the left hemisphere. The present results support the prominent role of the PFC and, specifically, the MFG in working memory, and indicate that the mnemonic content of the task affects the relative weighting of hemispheric activation.