未服用药物的重度抑郁症患者尾状核和伏隔核对奖励的反应降低。
Reduced caudate and nucleus accumbens response to rewards in unmedicated individuals with major depressive disorder.
作者信息
Pizzagalli Diego A, Holmes Avram J, Dillon Daniel G, Goetz Elena L, Birk Jeffrey L, Bogdan Ryan, Dougherty Darin D, Iosifescu Dan V, Rauch Scott L, Fava Maurizio
机构信息
Department of Psychology, Harvard University, 1220 William James Hall, 33 Kirkland St., Cambridge, MA 02138, USA.
出版信息
Am J Psychiatry. 2009 Jun;166(6):702-10. doi: 10.1176/appi.ajp.2008.08081201. Epub 2009 May 1.
OBJECTIVE
Major depressive disorder is characterized by impaired reward processing, possibly due to dysfunction in the basal ganglia. However, few neuroimaging studies of depression have distinguished between anticipatory and consummatory phases of reward processing. Using functional MRI (fMRI) and a task that dissociates anticipatory and consummatory phases of reward processing, the authors tested the hypothesis that individuals with major depression would show reduced reward-related responses in basal ganglia structures.
METHOD
A monetary incentive delay task was presented to 30 unmedicated individuals with major depressive disorder and 31 healthy comparison subjects during fMRI scanning. Whole-brain analyses focused on neural responses to reward-predicting cues and rewarding outcomes (i.e., monetary gains). Secondary analyses focused on the relationship between anhedonic symptoms and basal ganglia volumes.
RESULTS
Relative to comparison subjects, participants with major depression showed significantly weaker responses to gains in the left nucleus accumbens and the caudate bilaterally. Group differences in these regions were specific to rewarding outcomes and did not generalize to neutral or negative outcomes, although relatively reduced responses to monetary penalties in the major depression group emerged in other caudate regions. By contrast, evidence for group differences during reward anticipation was weaker, although participants with major depression showed reduced activation to reward cues in a small sector of the left posterior putamen. In the major depression group, anhedonic symptoms and depression severity were associated with reduced caudate volume bilaterally.
CONCLUSIONS
These results suggest that basal ganglia dysfunction in major depression may affect the consummatory phase of reward processing. Additionally, morphometric results suggest that anhedonia in major depression is related to caudate volume.
目的
重度抑郁症的特征是奖赏处理受损，这可能是由于基底神经节功能障碍所致。然而，很少有关于抑郁症的神经影像学研究区分奖赏处理的预期阶段和消费阶段。作者使用功能磁共振成像（fMRI）和一项区分奖赏处理预期阶段和消费阶段的任务，检验了重度抑郁症患者在基底神经节结构中与奖赏相关的反应会减少这一假设。
方法
在fMRI扫描期间，向30名未接受药物治疗的重度抑郁症患者和31名健康对照受试者呈现金钱激励延迟任务。全脑分析聚焦于对奖赏预测线索和奖赏结果（即金钱收益）的神经反应。二级分析聚焦于快感缺失症状与基底神经节体积之间的关系。
结果
与对照受试者相比，重度抑郁症患者在左侧伏隔核和双侧尾状核中对收益的反应明显较弱。这些区域的组间差异特定于奖赏结果，并不适用于中性或负面结果，尽管在其他尾状核区域，重度抑郁症组对金钱惩罚的反应相对减少。相比之下，奖赏预期期间组间差异的证据较弱，尽管重度抑郁症患者在左侧后壳核的一个小区域对奖赏线索的激活减少。在重度抑郁症组中，快感缺失症状和抑郁严重程度与双侧尾状核体积减小有关。
结论
这些结果表明，重度抑郁症中的基底神经节功能障碍可能会影响奖赏处理的消费阶段。此外，形态学结果表明，重度抑郁症中的快感缺失与尾状核体积有关。
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