FIDMAG, Germanes Hospitalàries , Barcelona , Spain.
World J Biol Psychiatry. 2012 Dec;13(8):616-26. doi: 10.3109/15622975.2011.573808. Epub 2011 May 23.
Manic patients have been found to show reduced activation in the prefrontal cortex and other regions during performance of cognitive tasks. However, little is known about de-activations associated with the disorder. This study aimed to examine, at the whole-brain level, abnormal patterns of task-related activation and de-activation during performance of a working memory task.
Twenty-nine DSM-IV bipolar patients and 46 healthy controls underwent fMRI during performance of the n-back task. The patients were scanned while they were in a manic episode. Linear models were used to obtain maps of within-group activations and areas of differential activation between the groups.
The manic patients showed reduced activation compared to the controls in the bilateral dorsolateral prefrontal cortex and the right parietal cortex. They also showed failure of de-activation in the medial frontal cortex, extending to the temporal poles and parts of the limbic system bilaterally. The failure of activation in the dorsolateral prefrontal cortex disappeared when differences in task performance were controlled for in the analysis. However, the medial frontal failure of de-activation survived controlling for this.
This study suggests that, in addition to reduced prefrontal activation, failure of de-activation is an important functional imaging abnormality in mania. This, together with its location in the medial prefrontal cortex, implies default mode network dysfunction in the disorder.
研究发现，躁狂症患者在执行认知任务时，其前额叶皮层和其他区域的活动减少。然而，目前对于与该疾病相关的去激活现象知之甚少。本研究旨在在全脑水平上，研究执行工作记忆任务时与该疾病相关的异常激活和去激活模式。
29 名 DSM-IV 双相情感障碍患者和 46 名健康对照者在执行 n-back 任务时接受 fMRI 检查。在躁狂发作期间对患者进行扫描。使用线性模型获得组内激活图和组间差异激活区。
与对照组相比，躁狂症患者双侧背外侧前额叶皮层和右侧顶叶皮层的激活减少。他们还表现出内侧前额叶皮层去激活失败，延伸至双侧颞极和部分边缘系统。当分析中控制任务表现差异时，背外侧前额叶皮层的激活减少消失。然而，内侧前额叶的去激活失败仍然存在。
这项研究表明，除了前额叶激活减少外，去激活失败也是躁狂症的一个重要功能影像学异常。这一点，加上它位于内侧前额叶皮层，意味着该疾病中默认模式网络功能障碍。
