TY  - JOUR
PY  - 2017//
TI  - Patients with major depressive disorder exhibit reduced reward size coding in the striatum
JO  - Progress in neuro-psychopharmacology and biological psychiatry
A1  - Takamura, Masahiro
A1  - Okamoto, Yasumasa
A1  - Okada, Go
A1  - Toki, Shigeru
A1  - Yamamoto, Tetsuya
A1  - Ichikawa, Naho
A1  - Mori, Asako
A1  - Minagawa, Hideaki
A1  - Takaishi, Yoshiyuki
A1  - Fujii, Yasutaka
A1  - Kaichi, Yoko
A1  - Akiyama, Yuji
A1  - Awai, Kazuo
A1  - Yamawaki, Shigeto
SP  - 317
EP  - 323
VL  - 79
IS  - Pt B
N2  - BACKGROUND: Anhedonia is a core symptom of major depressive disorder (MDD). While recent evidence suggests that reduced motivation for reward may be a core feature of anhedonia, the abnormalities in modulatory neural responses to variable reward amounts in MDD patients remain unclear. We investigated whether MDD patients' ability to represent variable-sized monetary rewards in the striatum is disrupted. <br><br>METHODS: Twelve MDD patients and 12 healthy volunteers completed an assessment of psychometric status and participated in a functional magnetic resonance imaging (fMRI) task that involved the anticipation of financial reward (monetary incentive delay task). The size of the monetary reward was varied among trial conditions and was cued with geometric stimuli. Patients participated in additional fMRI sessions after a 6-week pharmacological treatment with escitalopram, an SSRI. <br><br>RESULTS: In healthy volunteers, striatal activity increased in proportion to the size of the monetary reward during reward anticipation. This pattern was altered in MDD patients, and significant group-by-reward size interaction effects were observed in the bilateral putamen and the left ventral striatum. Reward sensitivity in motor response and striatum activity at three regions were correlated in healthy controls. In MDD patients, this neurobehavioral coupling was not observed. In addition, changes in the neural reward sensitivity parameter at the left ventral striatum in response to treatment were positively correlated with a reduction of depressive symptoms. <br><br>CONCLUSIONS: Patients with MDD exhibit reduced ability to modulate neural response when adjusting for variable amount of reward. This result suggests that reward size coding in the striatum may represent a neural correlate of motivational anhedonia in MDD patients.<br><br>Copyright © 2017. Published by Elsevier Inc.<p />  <p>Language: en</p>
LA  - en
SN  - 0278-5846
UR  - http://dx.doi.org/10.1016/j.pnpbp.2017.07.006
ID  - ref1
ER  -