Neurocomputational mechanisms underlying subjective valuation of effort costs.
Neurocomputational mechanisms underlying subjective valuation of effort costs.
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DOI：
10.1371/journal.pbio.1002598
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发表时间：
2017-02
期刊：
影响因子：
9.8
通讯作者：
Husain M
中科院分区：
文献类型：
--
作者：
Chong TT;Apps M;Giehl K;Sillence A;Grima LL;Husain M
在日常生活中，我们必须决定是否值得付出努力来获得回报。努力可以在不同的领域中体验到，有些任务需要显著的认知需求，而其他任务则需要更多的体力劳动。努力获得回报的动机是高度主观的，在不同的行为领域中差异很大。然而，人们对不同的努力成本如何主观地与奖励进行权衡的计算或神经基础知之甚少。有没有一个共同的、通用的大脑区域系统来评估所有的成本和收益？在这里，我们使用计算模型和功能性磁共振成像（fMRI）来研究认知和物理领域的价值处理机制。参与者接受了两项新任务的训练，这些任务的认知或体力都有参数变化。在功能磁共振成像，参与者表明他们的偏好之间的一个固定的低努力/低回报的选项和一个可变的高努力/高回报提供每个努力域。重要的是，认知和身体努力导致的奖赏贬值是由一个共同的区域网络所促成的，包括背内侧和背外侧前额叶皮层、顶内沟和前额叶。这些领域内的活动一般领域也与奖励和积极的努力负相关，这表明这些参数在这些领域内的整合。此外，杏仁核似乎在处理与认知努力相关的奖励价值方面发挥着独特的、特定领域的作用。这些结果首次揭示了不同努力领域的主观成本效益评估的神经计算机制，并提供了对动机多维性质的洞察。基于模型的功能磁共振成像显示，认知和身体动机是由重叠的神经基质支撑的，但杏仁核在评估认知努力方面发挥着独特的作用。如果没有努力的动力，就很少能获得奖励。在人类中，努力可以在认知和身体领域被感知，但我们对大脑如何评估是否值得付出不同类型的努力来换取奖励知之甚少。在这项研究中，我们使用功能磁共振成像（fMRI），以确定努力处理的神经和计算基础。我们开发了两个新的任务，无论是认知或身体上的努力，并有参与者表明他们的偏好低努力/低回报与高努力/高回报版本的每一个。我们的研究结果显示，在不同的努力领域，奖励贬值的模式是不同的。此外，无论涉及哪种类型的努力，动机都是由一个跨越顶叶-前额叶皮层和前额叶皮层的重叠大脑区域组成的大型网络提供的。然而，我们也发现杏仁核在激发认知上而非身体上的努力行为方面发挥着独特的作用。这些数据通过揭示神经计算特征来影响当前基于价值的决策的神经经济学理论，这些神经计算特征是个体为获得奖励而付出不同类型努力的动机的可变性的基础。
In everyday life, we have to decide whether it is worth exerting effort to obtain rewards. Effort can be experienced in different domains, with some tasks requiring significant cognitive demand and others being more physically effortful. The motivation to exert effort for reward is highly subjective and varies considerably across the different domains of behaviour. However, very little is known about the computational or neural basis of how different effort costs are subjectively weighed against rewards. Is there a common, domain-general system of brain areas that evaluates all costs and benefits? Here, we used computational modelling and functional magnetic resonance imaging (fMRI) to examine the mechanisms underlying value processing in both the cognitive and physical domains. Participants were trained on two novel tasks that parametrically varied either cognitive or physical effort. During fMRI, participants indicated their preferences between a fixed low-effort/low-reward option and a variable higher-effort/higher-reward offer for each effort domain. Critically, reward devaluation by both cognitive and physical effort was subserved by a common network of areas, including the dorsomedial and dorsolateral prefrontal cortex, the intraparietal sulcus, and the anterior insula. Activity within these domain-general areas also covaried negatively with reward and positively with effort, suggesting an integration of these parameters within these areas. Additionally, the amygdala appeared to play a unique, domain-specific role in processing the value of rewards associated with cognitive effort. These results are the first to reveal the neurocomputational mechanisms underlying subjective cost–benefit valuation across different domains of effort and provide insight into the multidimensional nature of motivation. Model-based fMRI in humans shows that cognitive and physical motivation are underpinned by overlapping neural substrates, but the amygdala plays a unique role in valuation of cognitive effort. Rewards are rarely obtained without the motivation to exert effort. In humans, effort can be perceived in both the cognitive and physical domains, yet little is known about how the brain evaluates whether it is worth exerting different types of effort in return for rewards. In this study, we used functional magnetic resonance imaging (fMRI) to determine the neural and computational basis of effort processing. We developed two novel tasks that were either cognitively or physically effortful and had participants indicate their preference for a low-effort/low-reward versus a higher-effort/higher-reward version of each. Our results showed distinct patterns of reward devaluation across the different domains of effort. Furthermore, regardless of the type of effort involved, motivation was subserved by a large network of overlapping brain areas across the parieto-prefrontal cortex and insula. However, we also found that the amygdala plays a unique role in motivating cognitively—but not physically—effortful behaviours. These data impact current neuroeconomic theories of value-based decision making by revealing the neurocomputational signatures that underlie the variability in individuals’ motivation to exert different types of effort in return for reward.