School of Psychology, University of Queensland, St Lucia, Brisbane QLD 4072 Australia
School of Psychology, University of Queensland, St Lucia, Brisbane QLD 4072 Australia.
J Neurosci. 2023 Oct 11;43(41):6909-6919. doi: 10.1523/JNEUROSCI.1140-23.2023. Epub 2023 Aug 30.
Noninvasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS), show promise in treating a range of psychiatric and neurologic conditions. However, optimization of such applications requires a better understanding of how tDCS alters cognition and behavior. Existing evidence implicates dopamine in tDCS alterations of brain activity and plasticity; however, there is as yet no causal evidence for a role of dopamine in tDCS effects on cognition and behavior. Here, in a preregistered, double-blinded study, we examined how pharmacologically manipulating dopamine altered the effect of tDCS on the speed-accuracy trade-off, which taps ubiquitous strategic operations. Cathodal tDCS was delivered over the left prefrontal cortex and the superior medial frontal cortex before participants ( = 62, 24 males, 38 females) completed a dot-motion task, making judgments on the direction of a field of moving dots under instructions to emphasize speed, accuracy, or both. We leveraged computational modeling to uncover how our interventions altered latent decisional processes driving the speed-accuracy trade-off. We show that dopamine in combination with tDCS (but not tDCS alone nor dopamine alone) not only impaired decision accuracy but also impaired discriminability, which suggests that these manipulations altered the encoding or representation of discriminative evidence. This is, to the best of our knowledge, the first direct evidence implicating dopamine in the way tDCS affects cognition and behavior. tDCS can improve cognitive and behavioral impairments in clinical conditions; however, a better understanding of its mechanisms is required to optimize future clinical applications. Here, using a pharmacological approach to manipulate brain dopamine levels in healthy adults, we demonstrate a role for dopamine in the effects of tDCS in the speed-accuracy trade-off, a strategic cognitive process ubiquitous in many contexts. In doing so, we provide direct evidence implicating dopamine in the way tDCS affects cognition and behavior.
非侵入性脑刺激技术，如经颅直流电刺激（tDCS），在治疗一系列精神和神经疾病方面显示出希望。然而，此类应用的优化需要更好地了解 tDCS 如何改变认知和行为。现有证据表明多巴胺参与了 tDCS 对大脑活动和可塑性的改变；然而，目前尚无因果证据表明多巴胺在 tDCS 对认知和行为的影响中起作用。在这里，在一项预先注册的、双盲研究中，我们研究了药理学操纵多巴胺如何改变 tDCS 对速度-准确性权衡的影响，该权衡反映了普遍存在的策略操作。在参与者（= 62 人，24 名男性，38 名女性）完成点运动任务之前，给予左前额叶皮层和上内侧额皮质阴极 tDCS，根据指令判断运动点场的方向，强调速度、准确性或两者兼顾。我们利用计算模型来揭示我们的干预措施如何改变驱动速度-准确性权衡的潜在决策过程。我们表明，多巴胺与 tDCS 联合使用（而不是 tDCS 单独使用或多巴胺单独使用）不仅会损害决策准确性，还会损害辨别力，这表明这些操作改变了辨别证据的编码或表示。据我们所知，这是第一个直接证据表明多巴胺参与了 tDCS 影响认知和行为的方式。tDCS 可以改善临床条件下的认知和行为障碍；然而，需要更好地了解其机制，以优化未来的临床应用。在这里，我们使用药理学方法在健康成年人中操纵大脑多巴胺水平，证明了多巴胺在 tDCS 对速度-准确性权衡的影响中的作用，这是许多情况下普遍存在的一种策略性认知过程。通过这样做，我们提供了直接证据，表明多巴胺参与了 tDCS 影响认知和行为的方式。
