Pavlovian biases influence instrumental learning by coupling reward seeking with action invigoration and punishment avoidance with action suppression. Using a probabilistic go/no-go task designed to orthogonalize action (go/no-go) and valence (reward/punishment), recent studies have shown that the interaction between the two is dependent on the striatum and its key neuromodulator dopamine. Using this task, we sought to identify how structural and neuromodulatory age-related differences in the striatum may influence Pavlovian biases and instrumental learning in 25 young and 31 older adults. Computational modeling revealed a significant age-related reduction in reward and punishment sensitivity and marked (albeit not significant) reduction in learning rate and lapse rate (irreducible noise). Voxel-based morphometry analysis using 7 Tesla MRI images showed that individual differences in learning rate in older adults were related to the volume of the caudate nucleus. In contrast, dopamine synthesis capacity in the dorsal striatum, assessed using [18F]-DOPA positron emission tomography in 22 of these older adults, was not associated with learning performance and did not moderate the relationship between caudate volume and learning rate. This multiparametric approach suggests that age-related differences in striatal volume may influence learning proficiency in old age.

中文翻译：

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纹状体在学习正交化作用和价态中的作用：结合 PET 和 7 T MRI 老化研究。

巴甫洛夫偏差通过将奖励寻求与行动激励和惩罚回避与行动抑制相结合来影响工具学习。使用旨在将动作（go/no-go）和效价（奖励/惩罚）正交化的概率去/不去任务，最近的研究表明，两者之间的相互作用取决于纹状体及其关键的神经调节剂多巴胺。使用这项任务，我们试图确定纹状体中与年龄相关的结构和神经调节差异如何影响 25 名年轻人和 31 名老年人的巴甫洛夫偏见和工具学习。计算模型揭示了与年龄相关的奖励和惩罚敏感性的显着降低，并且显着（尽管不显着）降低了学习率和失效率（不可减少的噪声）。使用 7 特斯拉 MRI 图像进行的基于体素的形态测量分析表明，老年人学习率的个体差异与尾状核的体积有关。相比之下，使用 [18F]-DOPA 正电子发射断层扫描对这些老年人中的 22 名进行评估的背侧纹状体中的多巴胺合成能力与学习表现无关，并且没有缓和尾状核体积和学习率之间的关系。这种多参数方法表明，纹状体体积与年龄相关的差异可能会影响老年人的学习能力。与学习表现无关，也没有调节尾状核体积和学习率之间的关系。这种多参数方法表明，纹状体体积与年龄相关的差异可能会影响老年人的学习能力。与学习表现无关，也没有调节尾状核体积和学习率之间的关系。这种多参数方法表明，纹状体体积与年龄相关的差异可能会影响老年人的学习能力。