Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University of Graduate School of Medicine, Ube, Yamaguchi 7558505, Japan; Katakura Hospital, Ube, Yamaguchi 7550151, Japan.
Prog Neuropsychopharmacol Biol Psychiatry. 2014 Jan 3;48:51-6. doi: 10.1016/j.pnpbp.2013.09.011. Epub 2013 Sep 25.
Reduced motivation and blunted decision-making are key features of major depressive disorder (MDD). Patients with MDD show abnormal decision-making when given negative feedback regarding a reward. The brain mechanisms underpinning this behavior remain unclear. In the present study, we examined the association between rapid decision-making with negative feedback and brain volume in MDD.
Thirty-six patients with MDD and 54 age-, sex- and IQ-matched healthy subjects were studied. Subjects performed a rapid decision-making monetary task in which participants could make high- or low-risk choices. We compared between the 2 groups the probability that a high-risk choice followed negative feedback. In addition, we used voxel-based morphometry (VBM) to compare between group differences in gray matter volume, and the correlation between the probability for high-risk choices and brain volume.
Compared to the healthy group, the MDD group showed significantly lower probabilities for high-risk choices following negative feedback. VBM analysis revealed that the MDD group had less gray matter volume in the right medial prefrontal cortex and orbitofrontal cortex (OFC) compared to the healthy group. The right OFC volume was negatively correlated with the probability that a high-risk choice followed negative feedback in patients with MDD. We did not observe these trends in healthy subjects.
Patients with MDD show reduced motivation for monetary incentives when they were required to make rapid decisions following negative feedback. We observed a correlation between this reduced motivation and gray matter volume in the medial and ventral prefrontal cortex, which suggests that these brain regions are likely involved in the pathophysiology of aberrant decision-making in MDD.
动机降低和决策迟钝是重度抑郁症（MDD）的主要特征。当患者收到有关奖励的负面反馈时，他们的决策会异常。这种行为的大脑机制尚不清楚。在本研究中，我们研究了 MDD 患者中快速做出负面反馈决策与脑容量之间的关系。
研究了 36 名 MDD 患者和 54 名年龄、性别和智商匹配的健康对照者。参与者进行了一项快速决策货币任务，在此任务中，参与者可以做出高风险或低风险的选择。我们比较了两组在高风险选择后跟随负面反馈的概率。此外，我们使用基于体素的形态测量学（VBM）来比较两组之间的灰质体积差异，以及高风险选择的概率与大脑体积之间的相关性。
与健康组相比，MDD 组在负反馈后做出高风险选择的概率明显较低。VBM 分析显示，与健康组相比，MDD 组的右侧内侧前额叶皮层和眶额皮层（OFC）的灰质体积较小。MDD 患者的右侧 OFC 体积与负反馈后高风险选择的概率呈负相关。我们在健康受试者中没有观察到这些趋势。
MDD 患者在需要根据负面反馈快速做出决策时，对金钱奖励的动机降低。我们观察到这种动机降低与内侧和腹侧前额叶皮质的灰质体积之间存在相关性，这表明这些大脑区域可能与 MDD 中异常决策的病理生理学有关。
