Department of Psychology, University of California, Los Angeles, USA.
Department of Psychology, University of California, Los Angeles, USA.
Neuroimage. 2017 Feb 1;146:679-689. doi: 10.1016/j.neuroimage.2016.08.067. Epub 2016 Sep 14.
Adolescence is characterized by increased risky decision-making, enhanced mesolimbic response to risk and reward, increased perceived stress, and heightened physiological response to stress relative to other age groups. In adults, evidence suggests that acute stress increases risky decision-making by stress-induced increases of dopamine in regions implicated in reward processing and decision-making. Acute stress also increases risky decision-making in adolescents, but the underlying neurobiological mechanisms remained unexplored. In this study, daily self-reports of stress were documented in adolescents and adults. Participants completed two fMRI visits during which they performed a risky decision-making task: once each when they endorsed a high and low level of stress. Results revealed that adolescent males took more advantageous risks under high stress relative to low stress whereas adult males took fewer non-advantageous risks under high stress relative to low stress. Adolescent males also showed a stress-related decrease in prefrontal activation when making risky decisions from high stress to low stress while adult males maintained prefrontal activation when making risky decisions across stress conditions. Adolescent and adult females did not exhibit stress-related changes in risky decisions. Moreover, greater prefrontal activation under stress was associated with fewer non-advantageous risks taken under stress. Implications for risk-taking under stress are discussed in light of these findings.
青春期的特点是冒险决策增加，对风险和奖励的中脑边缘反应增强，感知到的压力增加，以及相对于其他年龄组，对压力的生理反应增强。在成年人中，有证据表明，急性应激通过增加与奖励处理和决策相关的区域中的多巴胺来增加冒险决策。急性应激也会增加青少年的冒险决策，但潜在的神经生物学机制仍未得到探索。在这项研究中，青少年和成年人每天都会记录压力的自我报告。参与者在两次 fMRI 访问期间完成了一项冒险决策任务：一次是在他们表示高压力和低压力时完成的。结果表明，与低压力相比，青少年男性在高压力下承担更多的有利风险，而成年男性在高压力下承担的非有利风险较少。与低压力相比，青少年男性在做出高压力到低压力的冒险决策时，前额叶激活也会出现与压力相关的下降，而成年男性在做出冒险决策时会保持前额叶激活。青少年和成年女性在冒险决策中没有表现出与压力相关的变化。此外，压力下的前额叶激活增加与压力下承担的非有利风险减少有关。根据这些发现，讨论了应激下冒险行为的意义。
