Dopamine and a Bias for Proximal Action in Cognitive Effort

项目摘要 有认知控制要求的任务被视为主观代价高昂。个人将避免更高的 要求，就像他们避免体力劳动一样。主观上夸大的成本削弱了 认知控制，破坏任务表现--这一影响已经在精神分裂症中得到了检验， 抑郁症、帕金森氏症和抑郁症。然而，尽管意义广泛，但人们对此知之甚少。 关于跟踪工作成本或调解决策以参与或坚持要求的机制 认知任务。大量证据表明，多巴胺信号传递瞬间 激励状态，可以抵消努力成本，从而促进体力和认知努力。然而，虽然 多巴胺已被证明可以增强认知控制，但矛盾的是，它似乎也会破坏 通过促进冲动的行动来控制。 这个项目的目的是检验一种假说，该假说可以调和多巴胺对 通过统一认知领域和身体领域的行动选择机制进行认知控制。 也就是说，我将检验这样一种假设，即多巴胺偏向在作用过程中受益于成本信息。 选择，但它优先选择“最近的”动作(那些立即由 环境)。这一假设统一了领域，因为物理动作通常是由 环境(例如手边的杠杆或脚下的楼梯)，而控制动作不是。相反，在 在认知领域，控制行动必须与环境建议的东西竞争，并且只会赢 当控制机制做出足够快的反应时，它就会退出。这一假设的一个重要推论是 非常高的多巴胺水平可以放大就近距离的微小差异，从而增强近端 以及解释为什么多巴胺有时会削弱控制力 而不是宣传它。 我将通过在生物受限的神经网络模型中形式化原理来检验这一假设， 并测试它们是否能解释现有数据集中的神经生理和行为动力学。 在一系列实验中，我将测量和操作多巴胺(使用PET成像和 药物干预)以及测量和操纵接近度(通过眼睛凝视和任务设计)， 以确定邻近性和多巴胺是否如假设的那样决定认知行为选择。 最后，用我的实验数据检验了神经网络模型是否能预测性能 使用一组通用的参数。这项工作的长期好处将是准确地阐明 多巴胺可以影响费力的认知行为并产生靶点的机制 促进理想的努力行动而不同时促进冲动的药物干预。

Project Summary Tasks with cognitive control demands are treated as subjectively costly. Individuals will avoid higher demands, just like they avoid physical effort. Subjectively exaggerated costs sap motivation for cognitive control, undermining task performance – an effect that has been examined in schizophrenia, depression, Parkinson’s disease, and depression. Yet, despite widespread significance, little is known about mechanisms tracking effort costs or mediating decisions to engage or persist with demanding cognitive tasks. Numerous lines of evidence suggest that dopamine signaling, conveying momentary incentive state, can offset effort costs and thus promote physical and cognitive effort. However, while dopamine has been shown to enhance cognitive control, it also appears to, paradoxically, undermine control by promoting impulsive action. The purpose of this project is to test a hypothesis that can reconcile conflicting effects of dopamine on cognitive control by unifying action selection mechanisms in the cognitive and physical domain. Namely, I will test the hypothesis that dopamine biases benefit over cost information during action selection, but it does so preferentially for “proximal” actions (those that are immediately suggested by the environment). This hypothesis unifies domains in that physical actions are typically suggested by the environment (e.g. levers at hand, or stairs underfoot), while control actions are not. Instead, in the cognitive domain, control actions must compete with what the environment suggests, and will only win out when control mechanisms respond quickly enough. An important corollary of the hypothesis is that very high dopamine levels can amplify even small differences in proximity, thus potentiating proximal “habits” over “controlled” actions and explaining why dopamine can sometimes undermine control rather than promote it. I will test this hypothesis by formalizing the principles in biologically-constrained neural network models, and testing whether they can explain neurophysiological and behavioral dynamics in existing data sets. In a series of experiments, I will measure and manipulate dopamine (with PET imaging and pharmacological interventions) and measure and manipulate proximity (with eye gaze and task design), to determine whether proximity and dopamine determine cognitive action selection as hypothesized. Finally, I test whether the neural network models can predict performance in my experimental data using a common set of parameters. A long-term benefit of this work will be to precisely articulate the mechanisms by which dopamine can affect effortful cognitive action, and generate targets for pharmacological interventions that promote desirable effortful action without also promoting impulsivity.