Weak reward source memory in depression reflects blunted activation of VTA/SN and parahippocampus
Weak reward source memory in depression reflects blunted activation of VTA/SN and parahippocampus
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DOI：
10.1093/scan/nst155
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发表时间：
2014-10-01
影响因子：
4.2
通讯作者：
Pizzagalli, Diego A.
中科院分区：
文献类型：
--
作者：
Dillon, Daniel G.;Dobbins, Ian G.;Pizzagalli, Diego A.
内侧颞叶和多巴胺能中脑的奖励反应促进健康成年人的情景记忆形成，而抑郁症患者对情感积极材料的记忆薄弱表明这种机制可能在重度抑郁症（MDD）中功能失调。为了验证这一假设，我们进行了一项研究，在这项研究中，未接受药物治疗的MDD成人和健康对照组在功能性磁共振成像过程中编码与奖励或零标记配对的图画。在识别测试中，参与者判断绘画是否与奖励令牌（“奖励源”）或零令牌（“零源”）相关联。与对照组不同的是，抑郁的参与者对来自奖励来源的绘画的记忆力并没有比零来源的更好。与预测一致，控制也显示出更强的编码响应奖励令牌与零令牌在右侧海马和多巴胺能中脑，而MDD组显示相反的模式，更强的响应零与奖励令牌在这些地区。奖励与零令牌的多巴胺能中脑的差异激活与对照组的奖励源记忆优势呈正相关，但不抑郁的参与者。这些数据表明，抑郁症患者对阳性材料的记忆较弱，反映了多巴胺能中脑和内侧颞叶的编码反应迟钝。
Reward responses in the medial temporal lobes and dopaminergic midbrain boost episodic memory formation in healthy adults, and weak memory for emotionally positive material in depression suggests this mechanism may be dysfunctional in major depressive disorder (MDD). To test this hypothesis, we performed a study in which unmedicated adults with MDD and healthy controls encoded drawings paired with reward or zero tokens during functional magnetic resonance imaging. In a recognition test, participants judged whether drawings were previously associated with the reward token ('reward source') or the zero token ('zero source'). Unlike controls, depressed participants failed to show better memory for drawings from the reward source vs the zero source. Consistent with predictions, controls also showed a stronger encoding response to reward tokens vs zero tokens in the right para-hippocampus and dopaminergic midbrain, whereas the MDD group showed the opposite pattern-stronger responses to zero vs reward tokens-in these regions. Differential activation of the dopaminergic midbrain by reward vs zero tokens was positively correlated with the reward source memory advantage in controls, but not depressed participants. These data suggest that weaker memory for positive material in depression reflects blunted encoding responses in the dopaminergic midbrain and medial temporal lobes.