Cognitive control and brain resources in major depression:: An fMRI study using the n-back task
Cognitive control and brain resources in major depression:: An fMRI study using the n-back task
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DOI：
10.1016/j.neuroimage.2005.02.048
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发表时间：
2005-07-01
期刊：
影响因子：
5.7
通讯作者：
Dubois, B
中科院分区：
文献类型：
--
作者：
Harvey, PO;Fossati, P;Dubois, B
几项神经影像学研究报告了与对照组相比，抑郁症患者在进行认知挑战时的“前额叶功能减退”。抑郁症中的前额功能减退可能与行为表现受损有关。目前还不清楚这种受损的表现是额叶功能减退的结果还是原因。因此，我们建议在控制表现水平的同时，比较抑郁症患者和健康受试者的大脑活动。10名符合DSM-IV标准的重度抑郁症患者和10名健康对照者在fMRI扫描期间接受了n-back任务的口头版本测试。在整个实验中（1，2，3-back），工作记忆负荷被操纵，以增加认知需求。在1.5-T GE扫描仪上采集fMRI数据，并使用SPM 99软件进行分析。我们没有发现任何组之间的性能和反应时间的n-back任务的复杂性的每一个级别的差异。抑郁症患者和对照组显示双侧激活的外侧前额叶皮层，前扣带回和顶叶皮层。这些区域的激活受到任务复杂性的调节。在这个n-back神经网络中，与健康受试者相比，抑郁症患者的外侧前额叶皮层和前扣带回表现出更大的激活。这项研究提供的证据表明，抑郁症患者需要在同一个神经网络内更大的激活，以保持在工作记忆任务中与对照组相似的表现水平。我们的研究结果表明，抑郁症可能会损害抑郁症患者的认知能力，在认知控制过程中比对照组招募更多的大脑资源。(c)2005年爱思唯尔公司All rights reserved.
Several neuroimaging studies have reported 'hypofrontality' in depressed patients performing a cognitive challenge compared to control subjects. Hypofrontality in depression is likely associated with an impaired behavioral performance. It is unclear whether this impaired performance is the consequence or the cause of hypofrontality. Consequently, we proposed to compare the cerebral activity of depressed patients and healthy subjects while controlling for the level of performance. Ten individuals meeting DSM-IV criteria for Major Depression and 10 healthy controls were tested with a verbal version of the n-back task during fMRI scanning. The working memory load was manipulated across the experiment (1,2,3-back) to increase the cognitive demands. fMRI data were acquired on a 1.5-T GE scanner and analyzed using SPM99 software. We did not find any difference between groups in both performance and reaction times for each level of complexity of the n-back task. Depressed patients and control subjects showed bilateral activation of the lateral prefrontal cortex, anterior cingulate and parietal cortex. Activation of these regions was modulated by the complexity of the task. Within this n-back neural network, depressed patients showed greater activation of the lateral prefrontal cortex and the anterior cingulate compared to healthy subjects. This study provides evidence that depressed patients need greater activation within the same neural network to maintain a similar level of performance as controls during a working memory task. Our findings suggest that depression may impair the cognitive capacity of depressed patients by recruiting more brain resources than controls during cognitive control. (c) 2005 Elsevier Inc. All rights reserved.