Department of Clinical Psychology, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, Tübingen, Germany.
Biol Psychiatry. 2013 Apr 1;73(7):646-51. doi: 10.1016/j.biopsych.2012.10.010. Epub 2012 Dec 6.
Deficient cognitive control over emotional distraction is a central characteristic of major depressive disorder (MDD). Hypoactivation of the dorsolateral prefrontal cortex (dlPFC) has been linked with this deficit. In this study, we aimed to enhance the activity of the dlPFC in MDD patients by anodal transcranial direct current stimulation (tDCS) and thus ameliorate cognitive control.
In a double-blinded, balanced, randomized, sham-controlled crossover trial, we determined the effect of a single-session tDCS to the left dlPFC on the cognitive control in 22 MDD patients and 22 healthy control subjects. To assess the cognitive control, we used a delayed response working memory task with pictures of varying content (emotional vs. neutral) presented during the delay period.
Emotional pictures presented during the delay period impaired accuracy and response time of patients with MDD, indicating an attentional bias for emotional stimuli. Anodal tDCS to the dlPFC was associated with an enhanced working memory performance both in patients and control subjects. Specifically in subjects with MDD, the attentional bias was completely abolished by anodal tDCS.
The present study demonstrates that anodal tDCS applied to the left dlPFC improves deficient cognitive control in MDD. Based on these data, tDCS might be suitable to support the effects of behavioral training to enhance cognitive control in MDD.
情绪分心的认知控制不足是重度抑郁症（MDD）的一个核心特征。背外侧前额叶皮层（dlPFC）的活动不足与这种缺陷有关。在这项研究中，我们旨在通过阳极经颅直流电刺激（tDCS）增强 MDD 患者的 dlPFC 活性，从而改善认知控制。
在一项双盲、平衡、随机、假刺激对照交叉试验中，我们确定了单次 tDCS 对左侧 dlPFC 对 22 名 MDD 患者和 22 名健康对照受试者认知控制的影响。为了评估认知控制，我们使用了一个带有不同内容（情绪与中性）图片的延迟反应工作记忆任务，这些图片在延迟期间呈现。
情绪图片在延迟期间损害了 MDD 患者的准确性和反应时间，表明对情绪刺激存在注意力偏向。dlPFC 的阳极 tDCS 与患者和对照组的工作记忆表现增强有关。具体来说，在 MDD 患者中，阳极 tDCS 完全消除了注意力偏向。
本研究表明，应用于左侧 dlPFC 的阳极 tDCS 可改善 MDD 中认知控制不足的问题。基于这些数据，tDCS 可能适合支持行为训练的效果，以增强 MDD 中的认知控制。
