Blair K S, Finger E, Marsh A A, Morton J, Mondillo K, Buzas B, Goldman D, Drevets W C, Blair R J R
Department of Health and Human Services, Mood and Anxiety Program, National Institute of Mental Health, National Institutes of Health, 15K North Drive, Room 300A, MSC 2670, Bethesda, MD 20892-2670, USA.
Psychopharmacology (Berl). 2008 Jan;196(1):29-38. doi: 10.1007/s00213-007-0920-y. Epub 2007 Oct 17.
The serotonin (5-HT) system is considered important for decision-making. However, its role in reward- and punishment-based processing has not yet been clearly determined.
The present study examines the effect of 5-HTTLPR genotype and tryptophan depletion on reward- and punishment-related processing, using a task that considers decision-making in situations of subtlety of choice. Thus, it considers that response choice often occurs in situations where both options are desirable (e.g., choosing between mousse au chocolat or crème caramel cheesecake from a menu) or undesirable. It also considers that response choice is easier when the reinforcements associated with the options are far apart, rather than close, in value.
Healthy volunteers underwent acute tryptophan depletion (ATD) or control procedures and genotyping of the 5-HTTLPR for long and short allele variants. We then examined the effects and interactions of ATD and the serotonin promoter polymorphism genotype on two aspects of decision-making: (a) decision form, choosing between two objects to gain the greater reward or lesser punishment and (b) between-object reinforcement distance, the difference in reinforcements associated with two options.
ATD and LL homozygosity had comparable interactions with decision form and between-object reinforcement distance. Specifically, both modulated the effect of between-object reinforcement distance when deciding between objects both associated with punishment. Moreover, ATD and genotype interacted with ATD disproportionately affecting the performance of the LL homozygous group.
These results suggest that serotonin is particularly associated with punishment, rather than reward-related processing, and that individual sensitivity to punishment-related information and tryptophan depletion varies with genotype.
血清素（5-羟色胺，5-HT）系统被认为对决策很重要。然而，其在基于奖励和惩罚的处理过程中的作用尚未明确确定。
本研究使用一项考虑在选择微妙情况下进行决策的任务，考察5-HTTLPR基因型和色氨酸耗竭对与奖励和惩罚相关处理的影响。因此，它认为反应选择通常发生在两种选择都合意的情况（例如，从菜单中选择巧克力慕斯或焦糖奶油芝士蛋糕）或都不合意的情况。它还认为，当与选项相关的强化物在价值上相差较大而非接近时，反应选择会更容易。
健康志愿者接受急性色氨酸耗竭（ATD）或对照程序，并对5-HTTLPR的长等位基因和短等位基因变体进行基因分型。然后，我们考察了ATD和血清素启动子多态性基因型对决策两个方面的影响及相互作用：（a）决策形式，在两个对象之间进行选择以获得更大奖励或更小惩罚；（b）对象间强化距离，与两个选项相关的强化物差异。
ATD和LL纯合性在决策形式和对象间强化距离方面具有可比的相互作用。具体而言，在对两个都与惩罚相关的对象进行决策时，二者均调节了对象间强化距离的影响。此外，ATD和基因型相互作用，ATD对LL纯合组的表现影响不成比例。
这些结果表明，血清素尤其与惩罚而非奖励相关处理有关，并且个体对惩罚相关信息的敏感性和色氨酸耗竭随基因型而变化。
