Neural mechanisms of individual differences in temporal discounting of monetary and primary rewards in adolescents
Neural mechanisms of individual differences in temporal discounting of monetary and primary rewards in adolescents
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DOI：
10.1016/j.neuroimage.2017.04.013
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发表时间：
2017-06-01
期刊：
影响因子：
5.7
通讯作者：
Scheres, Anouk
中科院分区：
文献类型：
--
作者：
de Water, Erik;Mies, Gabry W.;Scheres, Anouk
青少年一般都容易冲动。然而，冲动性是一个涉及多个组成过程的多维结构。这些成分中的哪一个导致了青少年的冲动，目前还不清楚。本研究的重点是时间折扣（TD）的不同组成部分，即，对较小的即时奖励的偏好超过较大的延迟奖励。参与者是58名青少年（12-16岁），他们在金钱和零食奖励的情况下进行了fMRI TD任务。使用混合效应模型，我们确定了参与者的平均不耐烦，并进一步将TD选择分解为：1）金额敏感性（即时奖励大小的独特贡献）; 2）延迟敏感性（延迟持续时间的独特贡献）。青少年的平均不耐烦与额顶叶和腹侧纹状体活动在延迟奖励选择，并与腹内侧前额叶皮层活动在立即奖励选择。青少年的数量敏感性与腹侧纹状体和背侧前扣带皮层在立即奖励选择过程中的活动呈正相关。延迟敏感性与下顶叶皮层活动在延迟奖励选择呈正相关。正如预期的那样，零食的折扣比金钱更陡峭，两种奖励类型的TD与顶叶皮层的重叠激活有关。探索睾酮或雌二醇是否与TD及其神经相关性相关，结果显示无显著相关性。这些研究结果表明，不同的组件有助于独特的TD选择和金额敏感性的个体差异是唯一与激活的奖励估价区，而延迟敏感性的个体差异是唯一与激活的认知控制区。
Adolescents are generally characterized as impulsive. However, impulsivity is a multi-dimensional construct that involves multiple component processes. Which of these components contribute to adolescent impulsivity is currently unclear. This study focused on the neural mechanisms underlying individual differences in distinct components of temporal discounting (TD), i.e., the preference for smaller immediate rewards over larger delayed rewards. Participants were 58 adolescents (12-16 years-old) who performed an fMRI TD task with both monetary and snack rewards. Using mixed-effects modeling, we determined participants' average impatience, and further decomposed TD choices into: 1) amount sensitivity (unique contribution of the magnitude of the immediate reward); and 2) delay sensitivity (unique contribution of delay duration). Adolescents' average impatience was positively correlated with frontoparietal and ventral striatal activity during delayed reward choices, and with ventromedial prefrontal cortex activity during immediate reward choices. Adolescents' amount sensitivity was positively associated with ventral striatal and dorsal anterior cingulate cortex activity during immediate reward choices. Delay sensitivity was positively correlated with inferior parietal cortex activity during delayed reward choices. As expected, snacks were discounted more steeply than money, and TD of both reward types was associated with overlapping activation in the inferior parietal cortex. Exploring whether testosterone or estradiol were associated with TD and its neural correlates revealed no significant associations. These findings indicate that distinct components contribute uniquely to TD choice and that individual differences in amount sensitivity are uniquely associated with activation of reward valuation areas, while individual differences in delay sensitivity are uniquely associated with activation of cognitive control areas.