Catecholaminergic Regulation of Learning Rate in a Dynamic Environment.
Catecholaminergic Regulation of Learning Rate in a Dynamic Environment.
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DOI：
10.1371/journal.pcbi.1005171
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发表时间：
2016-10
影响因子：
4.3
通讯作者：
Nieuwenhuis S
中科院分区：
文献类型：
--
作者：
Jepma M;Murphy PR;Nassar MR;Rangel-Gomez M;Meeter M;Nieuwenhuis S
不断变化的世界中的适应性行为需要灵活地调整学习速度以适应环境变化的速度。最近的研究探讨了各种环境因素决定新结果对现有信念（即“学习率”）影响的计算机制。然而，参与这一过程的大脑机制，特别是神经调节剂仍然很大程度上未知。儿茶酚胺、去甲肾上腺素和多巴胺对刺激引起的皮层反应的全脑神经生理学影响表明，儿茶酚胺系统能够很好地调节对环境变化的学习，但该系统作用的更直接证据很少。在这里，我们报告了一项采用药理学、头皮电生理学和计算模型 (N = 32) 的研究证据，该研究表明儿茶酚胺在学习率调节中发挥着重要作用。我们发现，脑电图的 P3 部分（皮层中结果诱发的阶段性儿茶酚胺释放的电生理指标）可以预测学习率，并正式调节预测误差大小对学习率的影响。 P3 幅度还介导了两个计算变量（捕获结果的意外性和先前存在的信念的不确定性）对学习率的影响。此外，儿茶酚胺活性的药理学操作会影响意外任务变化后的学习率，其方式取决于参与者的基线学习率。我们的研究结果为人类儿茶酚胺系统在学习率调节（作为环境变化的函数）中的因果作用提供了一致的证据。根据环境变化进行信念更新对于适应性行为至关重要。我们结合药理学、头皮电生理学和计算模型，研究了人类儿茶酚胺（去甲肾上腺素和多巴胺）系统在此过程中的作用。我们发现事件相关电位的 P3 成分（皮层中阶段性儿茶酚胺释放的电生理指标）可以预测学习率并介导预测误差幅度对学习率的影响。此外，儿茶酚胺活性的药理学操作会影响意外任务变化后的学习率，其方式取决于参与者的自然学习率。这些发现可能反映了环境变化后信念更新的儿茶酚胺能调节。
Adaptive behavior in a changing world requires flexibly adapting one’s rate of learning to the rate of environmental change. Recent studies have examined the computational mechanisms by which various environmental factors determine the impact of new outcomes on existing beliefs (i.e., the ‘learning rate’). However, the brain mechanisms, and in particular the neuromodulators, involved in this process are still largely unknown. The brain-wide neurophysiological effects of the catecholamines norepinephrine and dopamine on stimulus-evoked cortical responses suggest that the catecholamine systems are well positioned to regulate learning about environmental change, but more direct evidence for a role of this system is scant. Here, we report evidence from a study employing pharmacology, scalp electrophysiology and computational modeling (N = 32) that suggests an important role for catecholamines in learning rate regulation. We found that the P3 component of the EEG—an electrophysiological index of outcome-evoked phasic catecholamine release in the cortex—predicted learning rate, and formally mediated the effect of prediction-error magnitude on learning rate. P3 amplitude also mediated the effects of two computational variables—capturing the unexpectedness of an outcome and the uncertainty of a preexisting belief—on learning rate. Furthermore, a pharmacological manipulation of catecholamine activity affected learning rate following unanticipated task changes, in a way that depended on participants’ baseline learning rate. Our findings provide converging evidence for a causal role of the human catecholamine systems in learning-rate regulation as a function of environmental change. Belief updating in response to changes in the environment is crucial for adaptive behavior. We examined the role of the human catecholamine (norepinephrine and dopamine) systems in this process, using a combination of pharmacology, scalp electrophysiology and computational modeling. We found that the P3 component of the event-related potential—an electrophysiological index of phasic catecholamine release in the cortex—predicted learning rate and mediated the effect of prediction-error magnitude on learning rate. Furthermore, a pharmacological manipulation of catecholamine activity affected learning rate following unanticipated task changes, in a way that depended on participants’ natural learning rate. These findings may reflect the catecholaminergic regulation of belief updating following environmental change.
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影响因子：
10.6
作者：
Cools, Roshan;D'Esposito, Mark
通讯作者：
D'Esposito, Mark
影响因子：
16.6
作者：
Cavanagh, James F.;Masters, Sean E.;Frank, Michael J.
通讯作者：
Frank, Michael J.
DOI：
10.1016/0013-4694(94)90093-0
发表时间：
1994-03-01
期刊：
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
影响因子：
--
作者：
FORD, JM;SULLIVAN, EV;PFEFFERBAUM, A
通讯作者：
PFEFFERBAUM, A
影响因子：
56.9
作者：
ANLEZARK, GM;CROW, TJ;GREENWAY, AP
通讯作者：
GREENWAY, AP
影响因子：
5.7
作者：
De Taeye, Leen;Vonck, Kristl;Raedt, Robrecht
通讯作者：
Raedt, Robrecht