The role of serotonin in emotional processing

到目前为止，我们的工作已经研究了在情绪处理任务期间，使用急性色氨酸耗竭改变人类的色氨酸能系统对行为表现的影响。 此外，我们已经开始确定急性色氨酸耗竭对情绪处理的影响如何作为5-羟色胺转运蛋白基因型的函数而变化。 我们发现，基因型和急性色氨酸耗竭调制情绪处理的可分离成分，通过色氨酸耗竭改变5-羟色胺传输的影响往往是基因型依赖性的。 例如，虽然色氨酸缺失本身并不会破坏恐惧表达识别，但它确实会损害携带5-羟色胺转运蛋白基因短等位基因的个体的恐惧识别。 这表明，基因型或单独的多巴胺能传递的变化可能不一定足以影响社会线索的处理，但基因型可能会影响这一领域的情绪处理时，面临着药理学的挑战，或当血清素系统被改变。 在情绪和焦虑障碍的背景下，情绪处理的一种重要形式是强化处理。 奖励和惩罚的加工直接指导行为和决策，非典型强化加工发生在各种精神疾病中。 我们发现，通过急性色氨酸耗竭改变血清素系统改变了强化过程，并且在某些情况下，这种影响是基因型依赖的。 在过去12个月的工作中，我们使用功能性磁共振成像来确定色氨酸耗尽对神经区域的选择性影响，特别是那些参与表达处理，情绪注意和逆转学习的区域。

Our work thus far has investigated the effects of altering serotonergic systems in humans using acute tryptophan depletion on behavioral performance during emotional processing tasks. Additionally, we have begun to determine how acute tryptophan depletions effects on emotional processing vary as a function of serotonin transporter genotype. We have found that both genotype and acute tryptophan depletion modulated dissociable components of emotional processing and that the effects of altering serotonin transmission via tryptophan depletion were often genotype-dependent. For example, although tryptophan depletion in and of itself did not disrupt fear expression recognition, it did impair fear recognition in individuals who carried the short allele of the serotonin transporter gene. This indicates that genotype or changes in serotonergic transmission alone may not necessarily be sufficient to affect processing of social cues, but genotype may influence this domain of emotional processing when faced with a pharmacological challenge or when serotonin systems are altered. A form of emotional processing that is important in the context of mood and anxiety disorders is reinforcement processing. Processing reward and punishment directly guides behaviors and decision making, and atypical reinforcement processing occurs in a variety of psychiatric conditions. We have found that altering serotonin systems via acute tryptophan depletion altered reinforcement processing, and again that this effect was, in some cases, genotype dependent. In the work that has been on-going over the past 12 months, we have used functional magnetic resonance imaging to determine the selective effects of tryptophan depletion on neural regions particularly those engaged in expression processing, emotional attention and reversal learning.