Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026, China.
Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026, China; Department of Medical Psychology, Anhui Medical University, Hefei, Anhui 230032, China.
Neuroimage. 2017 Aug 15;157:1-12. doi: 10.1016/j.neuroimage.2017.05.041. Epub 2017 May 20.
Learning of prediction error (PE), including reward PE and risk PE, is crucial for updating the prediction in reinforcement learning (RL). Neurobiological and computational models of RL have reported extensive brain activations related to PE. However, the occurrence of PE does not necessarily predict updating the prediction, e.g., in a probability-known event. Therefore, the brain regions specifically engaged in updating the prediction remain unknown. Here, we conducted two functional magnetic resonance imaging (fMRI) experiments, the probability-unknown Iowa Gambling Task (IGT) and the probability-known risk decision task (RDT). Behavioral analyses confirmed that PEs occurred in both tasks but were only used for updating the prediction in the IGT. By comparing PE-related brain activations between the two tasks, we found that the rostral anterior cingulate cortex/ventral medial prefrontal cortex (rACC/vmPFC) and the posterior cingulate cortex (PCC) activated only during the IGT and were related to both reward and risk PE. Moreover, the responses in the rACC/vmPFC and the PCC were modulated by uncertainty and were associated with reward prediction-related brain regions. Electric brain stimulation over these regions lowered the performance in the IGT but not in the RDT. Our findings of a distributed neural circuit of PE processing suggest that the rACC/vmPFC and the PCC play a key role in updating the prediction through PE processing during decision making.
学习预测误差 (PE)，包括奖励 PE 和风险 PE，对于强化学习 (RL) 中的预测更新至关重要。RL 的神经生物学和计算模型报告了与 PE 相关的广泛脑激活。然而，PE 的发生并不一定预示着预测的更新，例如在概率已知的事件中。因此，大脑中专门用于更新预测的区域仍然未知。在这里，我们进行了两项功能磁共振成像 (fMRI) 实验，即概率未知的爱荷华赌博任务 (IGT) 和概率已知的风险决策任务 (RDT)。行为分析证实，这两种任务都出现了 PE，但仅在 IGT 中用于更新预测。通过比较这两种任务中与 PE 相关的脑激活，我们发现，前扣带皮质/腹内侧前额叶皮质 (rACC/vmPFC) 和后扣带皮质 (PCC) 仅在 IGT 中激活，与奖励和风险 PE 均有关。此外，rACC/vmPFC 和 PCC 的反应受到不确定性的调节，并与奖励预测相关的脑区有关。对这些区域进行电刺激会降低 IGT 中的表现，但不会降低 RDT 中的表现。我们关于 PE 处理分布式神经回路的发现表明，rACC/vmPFC 和 PCC 在决策过程中通过 PE 处理在更新预测方面起着关键作用。
