Chang Fang-Yu, Wiratman Winnugroho, Ugawa Yoshikazu, Kobayashi Shunsuke
Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan.
Department of Neurology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo Hospital, Jakarta, Indonesia.
Front Neurosci. 2021 Mar 19;15:552750. doi: 10.3389/fnins.2021.552750. eCollection 2021.
The decisions we make are sometimes influenced by interactions with other agents. Previous studies have suggested that the prefrontal cortex plays an important role in decision-making and that the dopamine system underlies processes of motivation, motor preparation, and reinforcement learning. However, the physiological mechanisms underlying how the prefrontal cortex and the dopaminergic system are involved in decision-making remain largely unclear. The present study aimed to determine how decision strategies influence event-related potentials (ERPs). We also tested the effect of levodopa, a dopamine precursor, on decision-making and ERPs in a randomized double-blind placebo-controlled investigation. The subjects performed a matching-pennies task against an opposing virtual computer player by choosing between right and left targets while their ERPs were recorded. According to the rules of the matching-pennies task, the subject won the trial when they chose the same side as the opponent, and lost otherwise. We set three different task rules: (1) with the alternation (ALT) rule, the computer opponent made alternating choices of right and left in sequential trials; (2) with the random (RAND) rule, the opponent randomly chose between right and left; and (3) with the GAME rule, the opponent analyzed the subject's past choices to predict the subject's next choice, and then chose the opposite side. A sustained medial ERP became more negative toward the time of the subject's target choice. A biphasic potential appeared when the opponent's choice was revealed after the subject's response. The ERPs around the subject's choice were greater in RAND and GAME than in ALT, and the negative peak was enhanced by levodopa. In addition to these medial ERPs, we observed lateral frontal ERPs tuned to the choice direction. The signals emerged around the choice period selectively in RAND and GAME when levodopa was administered. These results suggest that decision processes are modulated by the dopamine system when a complex and strategic decision is required, which may reflect decision updating with dopaminergic prediction error signals.
我们所做的决策有时会受到与其他主体互动的影响。先前的研究表明，前额叶皮层在决策中起重要作用，多巴胺系统是动机、运动准备和强化学习过程的基础。然而，前额叶皮层和多巴胺能系统如何参与决策的生理机制在很大程度上仍不清楚。本研究旨在确定决策策略如何影响事件相关电位（ERP）。我们还在一项随机双盲安慰剂对照研究中测试了多巴胺前体左旋多巴对决策和ERP的影响。受试者在记录ERP的同时，通过在左右目标之间进行选择，与一个虚拟的对手进行匹配硬币任务。根据匹配硬币任务的规则，当受试者选择与对手相同的一侧时，他们赢得试验，否则失败。我们设置了三种不同的任务规则：（1）交替（ALT）规则，计算机对手在连续试验中交替选择左右；（2）随机（RAND）规则，对手随机选择左右；（3）博弈（GAME）规则，对手分析受试者过去的选择以预测受试者的下一个选择，然后选择相反的一侧。在受试者做出目标选择时，持续的内侧ERP变得更负。当受试者做出反应后揭示对手的选择时，会出现双相电位。受试者选择周围的ERP在RAND和GAME条件下比在ALT条件下更大，并且左旋多巴增强了负峰。除了这些内侧ERP，我们还观察到了与选择方向相关的外侧额叶ERP。在给予左旋多巴时，这些信号在RAND和GAME条件下的选择期周围选择性地出现。这些结果表明，当需要进行复杂的策略性决策时，决策过程会受到多巴胺系统的调节，这可能反映了多巴胺能预测误差信号对决策的更新。
