Division of Experimental Psychology, Institute of Psychology, University of Tartu, Näituse-2, Tartu, 50409, Estonia.
Division of Experimental Psychology, Institute of Psychology, University of Tartu, Näituse-2, Tartu, 50409, Estonia.
Behav Brain Res. 2021 Jun 11;407:113255. doi: 10.1016/j.bbr.2021.113255. Epub 2021 Mar 18.
The exact mechanism how serotonergic and dopaminergic systems relate to one another in working memory (WM) updating is unknown. Platelet monoamine oxidase (MAO) has been used as a marker for central serotonergic capacity, and catechol-O-methyltransferase (COMT) as a marker for central dopaminergic capacity. This study aimed to describe the interaction of platelet MAO activity and COMT Val158Met genotype in visual working memory updating: the ability to replace old information with new within hundreds of milliseconds. Previous studies suggest that platelet MAO activity and COMT Val158Met genotype could have an interaction effect on working memory. However, there are no studies that have directly examined the interaction of these biomarkers in WM updating. We used a 2-back updating task with facial expressions and defined updating efficiency as response times for correct responses. 455 subjects from a population representative sample were included. Mixed models were used for data analysis with an aim to study the interaction of COMT Val158Met genotype (Val/Val, Val/Met and Met/Met) and the level of MAO activity (high vs low). Education, IQ, sex, simple reaction times, and overall updating accuracy were included as covariates. We found that the effect of COMT Val158Met on updating efficiency depends on the level of platelet MAO activity. Low MAO in contrast to high MAO was associated with an increase in updating efficiency in Val/Met but a decrease in Met/Met. The results are discussed in the context of serotonin and dopamine functions in brain regions related to WM. The findings support the view that serotonin modulates dopaminergic activation in updating and contribute to understanding the role of serotonin in PFC, top-down inhibitory signals, and its interactions with dopamine in WM processes.
血清素能和多巴胺能系统在工作记忆（WM）更新中如何相互关联的具体机制尚不清楚。血小板单胺氧化酶（MAO）已被用作中枢血清素能力的标志物，儿茶酚-O-甲基转移酶（COMT）则被用作中枢多巴胺能能力的标志物。本研究旨在描述血小板 MAO 活性与 COMT Val158Met 基因型在视觉工作记忆更新中的相互作用：即在数百毫秒内用新信息替换旧信息的能力。先前的研究表明，血小板 MAO 活性和 COMT Val158Met 基因型可能对工作记忆具有相互作用效应。然而，目前尚无研究直接检测这些生物标志物在 WM 更新中的相互作用。我们使用了一个带有面部表情的 2 回更新任务，并将更新效率定义为正确反应的反应时间。我们纳入了来自代表性人群样本的 455 名受试者。使用混合模型进行数据分析，旨在研究 COMT Val158Met 基因型（Val/Val、Val/Met 和 Met/Met）和 MAO 活性水平（高与低）的相互作用。教育、智商、性别、简单反应时间和整体更新准确性被纳入协变量。我们发现，COMT Val158Met 对更新效率的影响取决于血小板 MAO 活性的水平。与高 MAO 相比，低 MAO 与 Val/Met 的更新效率增加有关，但与 Met/Met 的更新效率降低有关。结果在与 WM 相关的大脑区域中涉及的血清素和多巴胺功能的背景下进行了讨论。这些发现支持了这样一种观点，即血清素调节更新过程中多巴胺的激活，并有助于理解血清素在 PFC 中的作用、自上而下的抑制信号及其与 WM 过程中多巴胺的相互作用。
