Neural mechanisms of reinforcement learning under mortality threat
Neural mechanisms of reinforcement learning under mortality threat
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DOI：
10.1080/17470919.2019.1668846
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发表时间：
2019-09-18
影响因子：
2
通讯作者：
Han, Shihui
中科院分区：
文献类型：
--
作者：
Gao, Tianyu;Zhou, Yuqing;Han, Shihui
强化学习--对奖惩反馈做出反应而调整行为--对我们的生存至关重要。目前的工作调查了强化学习是否以及如何受到危及生存的死亡想法的影响。我们记录了成年人在执行概率学习任务时的脑电，这项任务要求在两种视觉模式之间进行强制选择，以获得不同受益者(即，自我、陌生人或没有人)的金钱奖励，然后再进行奖励或无奖励反馈。我们发现，对死亡的口头提醒(与消极情绪相比)扩大了枕叶电极上的早期正向成分(P1)，但降低了额叶中央电极上的晚期正向电位(LPP)，以响应学习刺激。虽然与奖励反馈刺激相关的无奖励反馈在所有受益者的奖励学习过程中引发了反馈相关负波(FRN)，并增加了额叶中央电极的非锁相theta带(4-8赫兹)活动，但口头提醒死亡(与负面情绪相比)显著降低了FRN幅度，但未能调节theta带的活动。这些结果表明，在强化学习中，死亡率显著增强了早期的注意加工，但抑制了对学习刺激的晚期认知评估。此外，死亡率显著降低了神经对反馈信号的敏感性，这些反馈信号表明缺乏金钱奖励。
Reinforcement learning - to adjust behaviors in response to feedback regarding reward and punishment - is pivotal to our survival. The present work investigated whether and how reinforcement learning is affected by thoughts of mortality that endanger one's survival. We recorded electroencephalographic while adults performed a probabilistic learning task that required a forced-choice between two visual patterns for monetary reward for different beneficiaries (i.e., self, stranger, or no one) followed by reward or no-reward feedback. We found that verbal reminders of mortality (vs. negative emotion) enlarged an early positive component (P1) at the occipital electrodes but decreased a late positive potential (LPP) at the frontocentral electrodes in response to learning stimuli. While no-reward feedback relative to reward feedback stimuli elicited a feedback-related negativity (FRN) and increased non-phase locked theta band (4-8 Hz) activity at the frontocentral electrodes during reward learning for all beneficiaries, verbal reminders of mortality (vs. negative emotion) significantly reduced the FRN amplitude but failed to modulate the theta band activity. These results suggest that mortality salience enhances early attentional processing but dampens late cognitive evaluation of the learning stimuli during reinforcement learning. Moreover, mortality salience decreases the neural sensitivity to feedback signaling the absence of monetary reward.