Hammar Åsa, Neto Emanuel, Clemo Leila, Hjetland Gunnhild J, Hugdahl Kenneth, Elliott Rebecca
Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.
Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
Psych J. 2016 Sep;5(3):191-205. doi: 10.1002/pchj.134. Epub 2016 Jun 13.
The present pilot study investigated neuronal correlates of executive functioning in patients previously diagnosed with recurrent major depressive disorder (MDD). The aim of the study was to examine a partially remitted and remitted MDD patient group with functional magnetic resonance imaging (fMRI) using a cognitive activation paradigm in order to probe aspects of response inhibition, attention shift, and working memory. Twenty MDD patients and 19 healthy controls, matched for age and sex, participated in the study. A working memory n-back task with single presentations of incongruent Stroop words was used, with the instruction to either remember the color of the ink the word was written in, or the color word itself, presented two or three words back in the presentation series. MR images were acquired on a 1.5-T GE Signa HD MR scanner. In addition to MR data, response time (RT) and response accuracy (RA) behavioral data were recorded. The behavioral results showed longer RT and lower RA in the MDD group compared to the control group across instruction conditions and working memory load. Based on previous studies of executive function, a composite region of interest (ROI) mask of the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), caudate, and putamen was used in statistical analysis. Significant activation was observed in controls throughout this corticostriatal network. When compared to controls, patients showed no significant difference in the level of activation in the ACC and the DLPFC. However, in the putamen and caudate, hypoactivation in the patient group was observed. It was concluded that these effects could be due to a scar effect as a result of previous episodes of MDD.
本初步研究调查了先前被诊断为复发性重度抑郁症(MDD)患者执行功能的神经相关性。该研究的目的是使用认知激活范式,通过功能磁共振成像(fMRI)检查部分缓解和已缓解的MDD患者组,以探究反应抑制、注意力转移和工作记忆方面的情况。20名MDD患者和19名年龄及性别匹配的健康对照参与了该研究。使用了一个工作记忆n-back任务,其中不一致的Stroop单词单次呈现,要求参与者记住单词书写所用墨水的颜色或颜色单词本身,在呈现序列中向前回溯两个或三个单词。在一台1.5-T的GE Signa HD MR扫描仪上采集MR图像。除了MR数据外,还记录了反应时间(RT)和反应准确性(RA)行为数据。行为结果显示,在不同指令条件和工作记忆负荷下,MDD组的RT比对照组更长,RA比对照组更低。基于先前对执行功能的研究,在统计分析中使用了前扣带回皮质(ACC)、背外侧前额叶皮质(DLPFC)、尾状核和壳核的复合感兴趣区域(ROI)掩码。在整个皮质纹状体网络中,对照组观察到显著激活。与对照组相比,患者在ACC和DLPFC的激活水平上没有显著差异。然而,在壳核和尾状核中,观察到患者组存在激活不足。研究得出结论,这些影响可能是由于先前MDD发作导致的瘢痕效应。