Subsecond dopamine fluctuations in human striatum encode superposed error signals about actual and counterfactual reward
Subsecond dopamine fluctuations in human striatum encode superposed error signals about actual and counterfactual reward
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DOI：
10.1073/pnas.1513619112
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发表时间：
2016-01-05
影响因子：
11.1
通讯作者：
Montague, P. Read
中科院分区：
文献类型：
--
作者：
Kishida, Kenneth T.;Saez, Ignacio;Montague, P. Read
在哺乳动物的大脑中，多巴胺是一种重要的神经调质，其作用是学习、决策和行为控制的基础。多巴胺神经元的变性导致帕金森病，而多巴胺信号传导的失调被认为有助于精神疾病，如精神分裂症，成瘾和抑郁症。动物模型的实验表明，人类纹状体中的多巴胺释放在正在进行的决策过程中编码奖励预测错误（RPE）（实际结果和预期结果之间的差异）。人体血氧水平依赖（BOLD）成像实验支持在纹状体中跟踪RPE的想法;然而，BOLD测量不能用于推断任何一种特定神经递质的作用。我们监测了帕金森病患者（n = 17）在执行顺序决策任务时的多巴胺水平。参与者下注并经历金钱收益或损失。纹状体中的多巴胺波动未能编码RPE，正如在模式生物中的大量工作所预期的那样。相反，亚秒多巴胺波动编码了RPE与反事实预测错误的整合，后者由经验结果可能会更好或更糟来定义。多巴胺的波动是如何联合收割机结合实际和反事实的是未知的。一种可能性是，这一过程是多巴胺神经元奖赏处理的正常行为，而此前并未在动物模型中进行过实验。或者，这种误差项的叠加可能是由多巴胺神经元的一个额外的尚未被识别的亚类引起的。
In the mammalian brain, dopamine is a critical neuromodulator whose actions underlie learning, decision-making, and behavioral control. Degeneration of dopamine neurons causes Parkinson's disease, whereas dysregulation of dopamine signaling is believed to contribute to psychiatric conditions such as schizophrenia, addiction, and depression. Experiments in animal models suggest the hypothesis that dopamine release in human striatum encodes reward prediction errors (RPEs) (the difference between actual and expected outcomes) during ongoing decision-making. Blood oxygen level-dependent (BOLD) imaging experiments in humans support the idea that RPEs are tracked in the striatum; however, BOLD measurements cannot be used to infer the action of any one specific neurotransmitter. We monitored dopamine levels with subsecond temporal resolution in humans (n = 17) with Parkinson's disease while they executed a sequential decision-making task. Participants placed bets and experienced monetary gains or losses. Dopamine fluctuations in the striatum fail to encode RPEs, as anticipated by a large body of work in model organisms. Instead, subsecond dopamine fluctuations encode an integration of RPEs with counterfactual prediction errors, the latter defined by how much better or worse the experienced outcome could have been. How dopamine fluctuations combine the actual and counterfactual is unknown. One possibility is that this process is the normal behavior of reward processing dopamine neurons, which previously had not been tested by experiments in animal models. Alternatively, this superposition of error terms may result from an additional yet-to-be-identified subclass of dopamine neurons.