How does the brain accommodate to increased task difficulty in word finding?: A functional MRI study
How does the brain accommodate to increased task difficulty in word finding?: A functional MRI study
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DOI：
10.1016/s1053-8119(04)00370-2
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发表时间：
2004-11-01
期刊：
影响因子：
5.7
通讯作者：
Knecht, S
中科院分区：
文献类型：
--
作者：
Dräger, B;Jansen, A;Knecht, S
在脑功能成像中，任务的难度可能对激活模式至关重要。任务难度的增加可能会导致特定任务区域的激活增加，或者导致额外的“代偿”区域的激活。先前的一项功能性经颅多普勒超声（frCD）研究显示，没有证据表明单词检索难度的增加会导致与语言相关区域同源的区域的增加。问题仍然是大脑如何适应不断增加的任务难度。由于fTCD方法的局限性，我们在本研究中使用了功能磁共振成像（fMRI）。我们操纵健康受试者（n = 14）的单词检索难度，以确定经典语言相关的大脑区域是否随着单词检索难度的增加而被激活。fMRI显示，随着任务难度的增加，(1)与语言相关的大脑激活的偏侧化保持不变，(2)优势半球的语言相关区域和亚优势半球的同源区域没有明显的额外激活，(3)在右侧后顶叶皮层发现了额外的激活，这通常与持续注意力和执行控制有关。因此，单词检索难度的增加导致不同大脑区域的共同激活，在一个大的认知网络中共同工作，而不是典型的语言相关区域的激活增加。(C) 2004爱思唯尔公司版权所有。
In functional imaging of the brain, the difficulty of a task may be critical for the pattern of activation. Increased task difficulty could lead to increased activation in task-specific regions or to activation of additional, "compensatory" regions. A previous study with functional transcranial Doppler sonography (frCD) showed no evidence that increased difficulty in word retrieval leads to a recruitment of areas homologous to language-related regions. The question remains how the brain accommodates increasing task difficulty. Because of limitations of fTCD method, we used functional magnetic resonance imaging (fMRI) in this study. We manipulated word retrieval difficulty in healthy subjects (n = 14) to determine whether the classical language-related brain regions are activated with increasing difficulty in word retrieval. fMRI demonstrated that with increased task difficulty(I) the lateralization of language-associated brain activation remained constant,(II) no additional activation of language-related regions of the dominant hemisphere, nor of homologous regions of the subdominant hemisphere, was evident,(III) additional activation was found in right posterior parietal cortex-typically associated with sustained attention and executive control.Thus, increased difficulty in word retrieval leads to coactivation of distinct brain areas, working together in a large cognitive network, rather than to increased activation of typically language-related areas. (C) 2004 Elsevier Inc. All rights reserved.