Institute of Social and Economic Research, Osaka University, Osaka 567-0047, Japan.
J Neurosci. 2009 Dec 16;29(50):15669-74. doi: 10.1523/JNEUROSCI.2799-09.2009.
Impairment in the serotonergic system has been linked to action choices that are less advantageous in a long run. Such impulsive choices can be caused by a deficit in linking a given reward or punishment with past actions. Here, we tested the effect of manipulation of the serotonergic system by tryptophan depletion and loading on learning the association of current rewards and punishments with past actions. We observed slower associative learning when actions were followed by a delayed punishment in the low serotonergic condition. Furthermore, a model-based analysis revealed a positive correlation between the length of the memory trace for aversive choices and subjects' blood tryptophan concentration. Our results suggest that the serotonergic system regulates the time scale of retrospective association of punishments to past actions.
血清素能系统的损伤与长期来看不太有利的行动选择有关。这种冲动的选择可能是由于将特定的奖励或惩罚与过去的行为联系起来的缺陷造成的。在这里,我们通过色氨酸耗竭和加载来测试血清素能系统对当前奖励和惩罚与过去行为之间关联学习的影响。我们观察到,在低血清素能状态下,当行为伴随着延迟的惩罚时,关联学习会变慢。此外,基于模型的分析显示,厌恶选择的记忆痕迹的长度与被试的血液色氨酸浓度之间存在正相关。我们的结果表明,血清素能系统调节了将惩罚与过去行为进行回溯关联的时间尺度。