Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
Department of Medicine, Yale University School of Medicine, New Haven, CT, USA; VA Connecticut Healthcare System, West Haven, CT, USA.
Neuroimage. 2020 Feb 15;207:116368. doi: 10.1016/j.neuroimage.2019.116368. Epub 2019 Nov 16.
Previous studies have suggested age-related differences in reward-directed behavior and cerebral processes in support of the age effects. However, it remains unclear how age may influence the processing of reward magnitude. Here, with 54 volunteers (22-74 years of age) participating in the Monetary Incentive Delay Task (MIDT) with explicit cues ($1, ¢1, or nil) and timed response to win, we characterized brain activations during anticipation and feedback and the effects of age on these regional activations. Behaviorally, age was associated with less reaction time (RT) difference between dollar and cent trials, as a result of slower response to the dollar trials; i.e., age was positively correlated with RT dollar - RT cent, with RT nil as a covariate. Both age and the RT difference ($1 - ¢1) were correlated with diminished activation of the right caudate head, right anterior insula, supplementary motor area (SMA)/pre-SMA, visual cortex, parahippocampal gyrus, right superior/middle frontal gyri, and left primary motor cortex during anticipation of $1 vs. ¢1 reward. Further, these regional activities mediated the age effects on RT differences. In responses to outcomes, age was associated with decreases in regional activations to dollar vs. cent loss but only because of higher age-related responses to cent losses. Together, these findings suggest age-related differences in sensitivity to the magnitude of reward. With lower cerebral responses during anticipation to win large rewards and higher responses to outcomes of small loss, aging incurs a constricted sensitivity to the magnitude of reward.
先前的研究表明，在奖励导向行为和支持年龄效应的大脑过程方面存在与年龄相关的差异。然而，目前尚不清楚年龄如何影响奖励幅度的处理。在这里，我们让 54 名志愿者（22-74 岁）参与了金钱激励延迟任务（MIDT），该任务具有明确的提示（$1、¢1 或无）和对赢得奖励的定时反应，我们描述了在预期和反馈期间大脑的激活情况，以及年龄对这些区域激活的影响。行为上，年龄与美元和分币试验之间的反应时间（RT）差异较小有关，原因是对美元试验的反应较慢；也就是说，年龄与 RT 美元 - RT 分币呈正相关，以 RT 无作为协变量。年龄和 RT 差异（$1-¢1）与右侧尾状核头、右侧前岛叶、补充运动区（SMA）/前 SMA、视觉皮层、海马旁回、右侧额上/中回和左侧初级运动皮层在预期$1 与¢1 奖励时的激活减少有关。此外，这些区域活动介导了年龄对 RT 差异的影响。在对结果的反应中，年龄与对美元与分币损失的区域激活减少有关，但这只是因为年龄相关的对分币损失的反应更高。总之，这些发现表明，对奖励幅度的敏感性存在与年龄相关的差异。在预期赢得大奖励时大脑反应较低，对小损失的结果反应较高，这使得对奖励幅度的敏感性受到限制。
