Gray matter volume and rapid decision-making in major depressive disorder.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University of Graduate School of Medicine, Ube, Yamaguchi 7558505, Japan; Katakura Hospital, Ube, Yamaguchi 7550151, Japan.
Masayuki
M
Nakano
Koji
K
Matsuo
Mami
M
Nakashima
Toshio
T
Matsubara
Kenichiro
K
Harada
Kazuteru
K
Egashira
Hiroaki
H
Masaki
Kanji
K
Takahashi
Yoshifumi
Y
Watanabe
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D002755:Choice Behavior / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology*; D003657:Decision Making / Q000502:physiology*; D003865:Major Depressive Disorder / Q000150:complications* / Q000473:pathology*; D005260:Female; D005717:Games, Experimental; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000473:pathology*
ACC; ANOVA; Decision-making; Depressive disorder; HRSD; Hamilton Rating Scale for Depression; JART; Japanese Adult Reading Test; MDD; Negative feedback; OFC; PFC; Prefrontal cortex; ROI; VBM; Voxel-based morphometry; analysis of variance; anterior cingulate cortex; major depressive disorder; orbitofrontal cortex; prefrontal cortex; region of interest; voxel-based morphometry