Departments of Psychology.
Psychiatry and.
J Neurosci. 2018 Mar 7;38(10):2471-2481. doi: 10.1523/JNEUROSCI.2200-17.2018. Epub 2018 Feb 12.
Adolescence is characterized by both maturation of brain structure and increased risk of negative outcomes from behaviors associated with impulsive decision-making. One important index of impulsive choice is delay discounting (DD), which measures the tendency to prefer smaller rewards available soon over larger rewards delivered after a delay. However, it remains largely unknown how individual differences in structural brain development may be associated with impulsive choice during adolescence. Leveraging a unique large sample of 427 human youths (208 males and 219 females) imaged as part of the Philadelphia Neurodevelopmental Cohort, we examined associations between delay discounting and cortical thickness within structural covariance networks. These structural networks were derived using non-negative matrix factorization, an advanced multivariate technique for dimensionality reduction, and analyzed using generalized additive models with penalized splines to capture both linear and nonlinear developmental effects. We found that impulsive choice, as measured by greater discounting, was most strongly associated with diminished cortical thickness in structural brain networks that encompassed the ventromedial prefrontal cortex, orbitofrontal cortex, temporal pole, and temporoparietal junction. Furthermore, structural brain networks predicted DD above and beyond cognitive performance. Together, these results suggest that reduced cortical thickness in regions known to be involved in value-based decision-making is a marker of impulsive choice during the critical period of adolescence. Risky behaviors during adolescence, such as initiation of substance use or reckless driving, are a major source of morbidity and mortality. In this study, we present evidence from a large sample of youths that diminished cortical thickness in specific structural brain networks is associated with impulsive choice. Notably, the strongest association between impulsive choice and brain structure was seen in regions implicated in value-based decision-making; namely, the ventromedial prefrontal and orbitofrontal cortices. Moving forward, such neuroanatomical markers of impulsivity may aid in the development of personalized interventions targeted to reduce risk of negative outcomes resulting from impulsivity during adolescence.
青春期的特点是大脑结构的成熟和与冲动决策相关的行为产生负面结果的风险增加。冲动选择的一个重要指标是延迟折扣（DD），它衡量的是更喜欢立即获得较小奖励而不是延迟后获得较大奖励的倾向。然而，个体大脑结构发育的差异如何与青春期的冲动选择有关，在很大程度上仍不清楚。利用费城神经发育队列中作为一部分成像的 427 名人类青少年（208 名男性和 219 名女性）的独特大样本，我们研究了延迟折扣与结构协变网络内皮质厚度之间的关联。这些结构网络是使用非负矩阵分解得出的，这是一种用于降维的高级多元技术，并使用带惩罚样条的广义加性模型进行分析，以捕捉线性和非线性发育效应。我们发现，冲动选择（由更大的折扣来衡量）与包括腹内侧前额叶皮层、眶额皮层、颞极和颞顶联合区在内的结构大脑网络中的皮质厚度降低最为密切相关。此外，大脑结构网络预测 DD 的效果优于认知表现。总的来说，这些结果表明，在基于价值的决策中涉及的区域中，皮质厚度的降低是青春期关键时期冲动选择的标志。青少年时期的危险行为，如开始使用物质或鲁莽驾驶，是发病率和死亡率的主要来源。在这项研究中，我们从大量青少年样本中提供了证据，表明特定结构大脑网络中的皮质厚度降低与冲动选择有关。值得注意的是，冲动选择与大脑结构之间最强的关联发生在涉及基于价值的决策的区域；即腹内侧前额叶和眶额皮层。从现在开始，冲动性的这种神经解剖学标志物可能有助于开发针对减少青春期冲动导致的负面结果的个性化干预措施。
