Center for Lifespan Psychology, Max Planck Institute for Human Development Berlin, Germany ; Department of Psychology, Technische Universität Dresden Dresden, Germany.
Front Psychol. 2013 Mar 4;4:89. doi: 10.3389/fpsyg.2013.00089. eCollection 2013.
Maximizing gains during probabilistic reinforcement learning requires the updating of choice - outcome expectations at the time when the feedback about a specific choice or action is given. Extant theories and evidence suggest that dopaminergic modulation plays a crucial role in reinforcement learning and the updating of choice - outcome expectations. Furthermore, recently a positive component of the event-related potential about 200 ms (P2) after feedback has been suggested to reflect such updating. The efficacy of dopaminergic modulation changes across the life span. However, to date investigations of age-related differences in feedback-related P2 during reinforcement learning are still scarce. The present study thus aims to investigate whether individual differences in the feedback-related P2 would be associated with polymorphic variations in a dopamine relevant gene PPP1R1B (also known as DARPP-32) and whether the genetic effect may differ between age groups. We observed larger P2 amplitudes in individuals carrying the genotype associated with higher dopamine receptor efficacy, i.e., a allele homozygotes of a single nucleotide polymorphism (rs907094) of the PPP1R1B gene. Moreover, this effect was more pronounced in children and older adults in comparison to adolescents and younger adults. Together, our findings indicate that polymorphic variations in a dopamine relevant gene are associated with individual differences in brain-evoked potentials of outcome updating and hint at the possibility that genotype effects on neurocognitive phenotypes may vary as a function of brain maturation and aging.
在概率强化学习中，要想获得最大收益，就需要在收到特定选择或行动的反馈时更新选择-结果预期。现有理论和证据表明，多巴胺能调制在强化学习和选择-结果预期的更新中起着关键作用。此外，最近有人提出，反馈后约 200 毫秒（P2）的事件相关电位的正成分反映了这种更新。多巴胺能调制的功效在整个生命周期中发生变化。然而，迄今为止，强化学习中与反馈相关的 P2 年龄相关性差异的研究仍然很少。因此，本研究旨在探讨个体在反馈相关的 P2 中是否存在差异，以及这种差异是否与多巴胺相关基因 PPP1R1B（也称为 DARPP-32）的多态性变异有关，以及遗传效应是否会因年龄组而有所不同。我们观察到，携带与更高多巴胺受体功效相关的基因型（即 PPP1R1B 基因的单核苷酸多态性（rs907094）的 a 等位基因纯合子）的个体的 P2 振幅更大。此外，与青少年和年轻人相比，这种效应在儿童和老年人中更为明显。总之，我们的研究结果表明，多巴胺相关基因的多态性与结果更新的脑诱发电位的个体差异有关，并暗示基因型对神经认知表型的影响可能随着大脑成熟和衰老而变化。
