Verstynen Timothy, Dunovan Kyle, Walsh Catherine, Kuan Chieh-Hsin, Manuck Stephen B, Gianaros Peter J
Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Carnegie Mellon Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Soc Cogn Affect Neurosci. 2020 Nov 10;15(10):1145-1156. doi: 10.1093/scan/nsaa088.
Unhealthy weight gain relates, in part, to how people make decisions based on prior experience. Here we conducted post hoc analysis on an archival data set to evaluate whether individual differences in adiposity, an anthropometric construct encompassing a spectrum of body types, from lean to obese, associate with signatures of asymmetric feedback learning during value-based decision-making. In a sample of neurologically healthy adults (N = 433), ventral striatal responses to rewards, measured using fMRI, were not directly associated with adiposity, but rather moderated its relationship with feedback-driven learning in the Iowa gambling task, tested outside the scanner. Using a biologically inspired model of basal ganglia-dependent decision processes, we found this moderating effect of reward reactivity to be explained by an asymmetrical use of feedback to drive learning; that is, with more plasticity for gains than for losses, stronger reward reactivity leads to decisions that minimize exploration for maximizing long-term outcomes. Follow-up analysis confirmed that individual differences in adiposity correlated with signatures of asymmetric use of feedback cues during learning, suggesting that reward reactivity may especially relate to adiposity, and possibly obesity risk, when gains impact future decisions more than losses.
不健康的体重增加部分与人们基于既往经验做出决策的方式有关。在此，我们对一个存档数据集进行了事后分析，以评估肥胖程度（一种涵盖从瘦到胖各种体型的人体测量指标）的个体差异是否与基于价值的决策过程中不对称反馈学习的特征相关。在一组神经功能正常的成年人样本（N = 433）中，使用功能磁共振成像（fMRI）测量的腹侧纹状体对奖励的反应与肥胖程度并无直接关联，而是在扫描仪外进行的爱荷华赌博任务中调节了其与反馈驱动学习的关系。通过使用一种受生物学启发的基底神经节依赖决策过程模型，我们发现奖励反应性的这种调节作用可通过不对称地利用反馈来驱动学习来解释；也就是说，收益比损失具有更大的可塑性，更强的奖励反应性会导致决策尽量减少探索以最大化长期结果。后续分析证实，肥胖程度的个体差异与学习过程中反馈线索不对称使用的特征相关，这表明当收益对未来决策的影响大于损失时，奖励反应性可能尤其与肥胖程度以及可能的肥胖风险相关。
