Probabilistic reward learning reflects the ability to adapt choices based on probabilistic feedback. The dopaminergically innervated corticostriatal circuit in the brain plays an important role in supporting successful probabilistic reward learning. Several components of the corticostriatal circuit deteriorate with age, as it does probabilistic reward learning. We showed previously that D1 receptor availability in NAcc predicts the strength of anticipatory value signaling in vmPFC, a neural correlate of probabilistic learning that is attenuated in older participants and predicts probabilistic reward learning performance. We investigated how white matter integrity in the pathway between nucleus accumbens (NAcc) and ventromedial prefrontal cortex (vmPFC) relates to the strength of anticipatory value signaling in vmPFC in younger and older participants. We found that in a sample of 22 old and 23 young participants, fractional anisotropy in the pathway between NAcc and vmPFC predicted the strength of value signaling in vmPFC independently from D1 receptor availability in NAcc. These findings provide tentative evidence that integrity in the dopaminergic and white matter pathways of corticostriatal circuitry supports the expression of value signaling in vmPFC which supports reward learning, however, the limited sample size calls for independent replication. These and future findings could add to the improved understanding of how corticostriatal integrity contributes to reward learning ability.

中文翻译：

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皮质纹状体白质完整性和多巴胺 D1 受体可用性预测奖励学习期间前额叶价值信号的年龄差异。

概率奖励学习反映了根据概率反馈调整选择的能力。大脑中多巴胺能神经支配的皮质纹状体回路在支持成功的概率奖励学习方面起着重要作用。皮质纹状体回路的几个组成部分会随着年龄的增长而恶化，因为它会进行概率奖励学习。我们之前表明，NAcc 中 D1 受体的可用性可预测 vmPFC 中预期价值信号的强度，这是概率学习的神经相关性，在老年参与者中减弱并预测概率奖励学习表现。我们研究了伏隔核 (NAcc) 和腹内侧前额叶皮层 (vmPFC) 之间通路中的白质完整性与年轻和年长参与者 vmPFC 中预期价值信号强度的关系。我们发现，在 22 名老年人和 23 名年轻参与者的样本中，NAcc 和 vmPFC 之间通路的各向异性分数预测了 vmPFC 中价值信号的强度，与 NAcc 中 D1 受体的可用性无关。这些发现提供了初步证据，表明皮质纹状体电路的多巴胺能和白质通路的完整性支持 vmPFC 中价值信号的表达，这支持奖励学习，但是，有限的样本量需要独立复制。