University of Birmingham Catecholaminergic challenge uncovers distinct Pavlovian and instrumental mechanisms of motivated (in)action
University of Birmingham Catecholaminergic challenge uncovers distinct Pavlovian and instrumental mechanisms of motivated (in)action
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发表时间：
2017
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通讯作者：
J. Swart;M. Froböse;J. Cook;D. Geurts;M. Frank;R. Cools;H. D. Ouden
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作者：
J. Swart;M. Froböse;J. Cook;D. Geurts;M. Frank;R. Cools;H. D. Ouden
儿茶酚胺调节动机线索对行动的影响。这种动机偏差被认为反映了基于线索的“巴甫洛夫”效应。在这里，我们评估动机偏差是否也可能产生于奖励和惩罚结果后主动和被动反应的不对称工具学习。我们提出了一个新的范式，使我们能够解开的影响，奖励和惩罚工具学习巴甫洛夫反应偏置。计算分析表明，动机偏见反映巴甫洛夫和工具的影响：奖励和惩罚线索促进广义（在）行动中的巴甫洛夫方式，而结果增强工具（联合国）学习的选择行动。这些线索和结果为基础的偏见被改变独立的儿茶酚胺增强剂哌甲酯。哌醋甲酯的作用因个体而异，其基线多巴胺合成能力、工作记忆广度是一个假定的替代指标。我们的研究揭示了动机影响行为的两种不同机制，并有助于完善目前的动机行为的儿茶酚胺能调制模型。
Catecholamines modulate the impact of motivational cues on action. Such motivational biases have been proposed to reflect cue-based, ‘Pavlovian’ effects. Here, we assess whether motivational biases may also arise from asymmetrical instrumental learning of active and passive responses following reward and punishment outcomes. We present a novel paradigm, allowing us to disentangle the impact of reward and punishment on instrumental learning from Pavlovian response biasing. Computational analyses showed that motivational biases reflect both Pavlovian and instrumental effects: reward and punishment cues promoted generalized (in)action in a Pavlovian manner, whereas outcomes enhanced instrumental (un)learning of chosen actions. These cue- and outcome-based biases were altered independently by the catecholamine enhancer melthylphenidate. Methylphenidate’s effect varied across individuals with a putative proxy of baseline dopamine synthesis capacity, working memory span. Our study uncovers two distinct mechanisms by which motivation impacts behaviour, and helps refine current models of catecholaminergic modulation of motivated action.