Prediction error as a linear function of reward probability is coded in human nucleus accumbens
Prediction error as a linear function of reward probability is coded in human nucleus accumbens
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DOI：
10.1016/j.neuroimage.2006.01.001
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发表时间：
2006-06-01
期刊：
影响因子：
5.7
通讯作者：
Spitzer, Manfred
中科院分区：
文献类型：
--
作者：
Abler, Birgit;Walter, Henrik;Spitzer, Manfred
猴子的多巴胺神经元编码了奖励概率。相位神经元激活不仅在预期奖励时随奖励概率线性增加，而且在忽略或收到奖励时也在概率范围内单调变化，因此建模了期望奖励和收到奖励之间的差异。这种预测误差的离散编码被认为是学习的基本原理之一。我们使用功能性磁共振成像（fMRI）显示，人类多巴胺系统以类似的方式编码奖励概率和预测误差。我们使用了一个简单的延迟激励任务，其奖励概率范围从0%到100%不等。人类伏隔核的活动与猴子神经元的相反应非常相似。首先，在任务预期期间，人类伏隔核（NAc）的fMRI信号随着奖励的概率线性增加。其次，在结果阶段，NAc中的活动将预测误差编码为奖励概率的线性函数。第三，我们发现Nac信号与感觉寻求和新奇寻求的个体差异相关，表明个体在概率范式下多巴胺系统的fMRI激活与先前认为与奖励处理相关的人格特征之间存在联系。因此，我们确定了两个不同的协变量来模拟Nac中的活动：心理任务的特定属性和个人性格特征。(c) 2006爱思唯尔公司版权所有。
Reward probability has been shown to be coded by dopamine neurons in monkeys. Phasic neuronal activation not only increased linearly with reward probability upon expectation of reward, but also varied monotonically across the range of probabilities upon omission or receipt of rewards, therefore modeling discrepancies between expected and received rewards. Such a discrete coding of prediction error has been suggested to be one of the basic principles of learning. We used functional magnetic resonance imaging (fMRI) to show that the human dopamine system codes reward probability and prediction error in a similar way. We used a simple delayed incentive task with a discrete range of reward probabilities from 0% to 100%. Activity in the nucleus accumbens of human subjects strongly resembled the phasic responses found in monkey neurons. First, during the expectation period of the task, the fMRI signal in the human nucleus accumbens (NAc) increased linearly with the probability of the reward. Second, during the outcome phase, activity in the NAc coded the prediction error as a linear function of reward probabilities. Third, we found that the Nac signal was correlated with individual differences in sensation seeking and novelty seeking, indicating a link between individual fMRI activation of the dopamine system in a probabilistic paradigm and personality traits previously suggested to be linked with reward processing. We therefore identify two different covariates that model activity in the Nac: specific properties of a psychological task and individual character traits. (c) 2006 Elsevier Inc. All rights reserved.