FIDMAG, Germanes Hospitalàries, Barcelona, Spain.
J Affect Disord. 2013 Jun;148(2-3):170-8. doi: 10.1016/j.jad.2012.04.009. Epub 2012 Jul 30.
Bipolar depression has been found to be associated with changes in prefrontal cortex activity during performance of cognitive tasks. However, the role of task-related de-activations has been little investigated.
Forty-one bipolar depressed patients and 41 matched normal controls underwent fMRI scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of within-group activations and areas of differential activation between the groups.
The bipolar depressed patients showed reduced activation in the dorsolateral prefrontal cortex (DLPFC) bilaterally and several other regions. After controlling for differences in task performance only differences in the DLPFC and cerebellum remained. Left DLPFC activation was inversely correlated with Hamilton and MADRS scores. The patients showed failure to de-activate in the medial prefrontal cortex, an area corresponding to the anterior medial node of the default mode network.
To confirm default mode network dysfunction demonstration of resting-state connectivity abnormalities would also be required. The study was carried out on treated patients, and did not assess for presence of depressive symptoms in the healthy controls.
Both prefrontal cortical and default mode network dysfunction appear to characterise bipolar depression. The former, but not the latter, is associated with symptom severity.
双相情感障碍患者在执行认知任务时，其前额叶皮层的活动会发生变化。然而，任务相关的去激活作用却很少被研究。
41 名双相情感障碍患者和 41 名匹配的正常对照者在执行基线、1 回和 2 回 n-back 任务时进行 fMRI 扫描。采用线性模型获得组内激活图和组间差异激活区。
双相情感障碍患者双侧背外侧前额叶皮层（DLPFC）和其他几个区域的激活减少。仅控制任务表现的差异后，DLPFC 和小脑的差异仍然存在。左侧 DLPFC 的激活与 Hamilton 和 MADRS 评分呈负相关。患者在前额叶内侧皮层（与默认模式网络的前内侧节点相对应的区域）未能去激活。
为了确认默认模式网络功能障碍，还需要证明静息状态连接异常。该研究是在接受治疗的患者中进行的，并未评估健康对照组中是否存在抑郁症状。
前额叶皮层和默认模式网络功能障碍似乎都能表征双相情感障碍。前者与症状严重程度有关，而后者则无关。
