Lipopolysaccharide Alters Motivated Behavior in a Monetary Reward Task: a Randomized Trial
Lipopolysaccharide Alters Motivated Behavior in a Monetary Reward Task: a Randomized Trial
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DOI：
10.1038/npp.2016.191
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发表时间：
2017-03-01
影响因子：
7.6
通讯作者：
Lekander, Mats
中科院分区：
文献类型：
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作者：
Lasselin, Julie;Treadway, Michael T.;Lekander, Mats
炎症引起的疾病与一系列行为改变有关；然而，它的动机方面在人类中仍然很少被研究。本研究采用双盲、安慰剂(生理盐水)对照的交叉设计，对21名健康受试者注射2 ng/kg体重的脂多糖(LPS)对动机的影响进行了评估。激励动机和奖励敏感性的测量使用奖励任务的努力支出(EEFRT)，其中高努力/高奖励试验与低努力/低奖励试验的动机受奖励大小和获胜概率的变化控制。由于困倦和动机之间的强烈交互作用，困倦的作用也被确定了。正如预期的那样，获胜的概率预测了参与高努力/高回报试验的选择；然而，这种情况在脂多糖注射后发生的程度比注射生理盐水后更大。这种影响与困倦程度有关。嗜睡增加了选择高努力/高回报反应模式的动机，但只有在获胜概率最高的时候才会。无论是直接还是通过困倦，脂蛋白对奖赏敏感性都没有影响。这些结果表明，脂多糖诱导的全身炎症导致健康青年受试者的动机改变，这种改变与嗜睡有关。因此，尽管疾病与节能行为有关，但当努力被认为是值得的时，疾病可以增加激励动力。
Inflammation-induced sickness is associated with a large set of behavioral alterations; however, its motivational aspects remain poorly explored in humans. The present study assessed the effect of lipopolysaccharide (LPS) administration at a dose of 2 ng/kg of body weight on motivation in 21 healthy human subjects in a double-blinded, placebo (saline)-controlled, cross-over design. Incentive motivation and reward sensitivity were measured using the Effort Expenditure for Rewards Task (EEfRT), in which motivation for high-effort/high-reward trials vs low-effort/low-reward trials are manipulated by variations in reward magnitude and,probability to win. Because of the strong interactions between sleepiness and motivation, the role of sleepiness was also determined. As expected, the probability to win predicted the choice to engage in high-effort/high-reward trials; however, this occurred at a greater extent after LPS than after saline administration. This effect was related to the level of sleepiness. Sleepiness increased motivation to choose the high-effort/high-reward mode of response, but only when the probability to win was the highest. LPS had no effect on reward sensitivity either directly or via sleepiness. These results indicate that systemic inflammation induced by LPS administration causes motivational changes in young healthy subjects, which are associated with sleepiness. Thus, despite its association with energy-saving behaviors, sickness allows increased incentive motivation when the effort is deemed worthwhile.