No unified reward prediction error in local field potentials from the human nucleus accumbens: evidence from epilepsy patients
No unified reward prediction error in local field potentials from the human nucleus accumbens: evidence from epilepsy patients
复制标题
人类伏隔核局部场电位没有统一的奖励预测误差：来自癫痫患者的证据
DOI：
10.1152/jn.00260.2015
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发表时间：
2015
影响因子：
2.5
通讯作者：
Dolan RJ
中科院分区：
文献类型：
--
作者：
Stenner MP;Rutledge RB;Zaehle T;Schmitt FC;Kopitzki K;Kowski AB;Voges J;Heinze HJ;Dolan RJ
功能性磁共振成像（fMRI）、循环伏安法和单单位电生理学研究表明，在基于价值的决策过程中，在脑桥核（Nacc）中测量的信号代表了奖励预测误差（RPE），即实际奖励和预测奖励之间的差异。在这里，我们研究了人类Nacc中奖励相关信号的精确时间和频谱模式。我们记录了当地的场电位（LFPs）从Nacc的6名癫痫患者在经济决策任务。在每一次试验中，患者都要决定是否接受或拒绝一场金钱收益或损失概率相等的赌博。四名患者的行为与价值期望指导下的选择一致。在这些患者中的3例中观察到结局发生前的预期值信号，在不同的潜伏期和不重叠的光谱模式。在所有受试者中，结果发生后的信号与RPE回归因子相关。然而，进一步的分析表明，这些信号更好地解释为结果效价，而不是RPE信号，与赌博收益和损失不同的功率β振荡和诱发反应幅度。两者合计，我们的研究结果不支持这样的想法，即突触后电位在Nacc代表一个RPE，统一的结果大小和先前的价值预期。我们讨论了我们的研究结果对健康个体的普遍性，以及我们的结果与用其他方法从Nacc获得的RPE信号测量的关系。
Functional magnetic resonance imaging (fMRI), cyclic voltammetry, and single-unit electrophysiology studies suggest that signals measured in the nucleus accumbens (Nacc) during value-based decision making represent reward prediction errors (RPEs), the difference between actual and predicted rewards. Here, we studied the precise temporal and spectral pattern of reward-related signals in the human Nacc. We recorded local field potentials (LFPs) from the Nacc of six epilepsy patients during an economic decision-making task. On each trial, patients decided whether to accept or reject a gamble with equal probabilities of a monetary gain or loss. The behavior of four patients was consistent with choices being guided by value expectations. Expected value signals before outcome onset were observed in three of those patients, at varying latencies and with nonoverlapping spectral patterns. Signals after outcome onset were correlated with RPE regressors in all subjects. However, further analysis revealed that these signals were better explained as outcome valence rather than RPE signals, with gamble gains and losses differing in the power of beta oscillations and in evoked response amplitudes. Taken together, our results do not support the idea that postsynaptic potentials in the Nacc represent a RPE that unifies outcome magnitude and prior value expectation. We discuss the generalizability of our findings to healthy individuals and the relation of our results to measurements of RPE signals obtained from the Nacc with other methods.