Department of Biomedical Engineering, Johns Hopkins School of Medicine, 773 North Broadway, Baltimore, MD, USA.
Kennedy Krieger Institute, 707 North Broadway, Baltimore, MD, USA.
Cereb Cortex. 2019 Sep 13;29(10):4277-4290. doi: 10.1093/cercor/bhy310.
The perceived effort level of an action shapes everyday decisions. Despite the importance of these perceptions for decision-making, the behavioral and neural representations of the subjective cost of effort are not well understood. While a number of studies have implicated anterior cingulate cortex (ACC) in decisions about effort/reward trade-offs, none have experimentally isolated effort valuation from reward and choice difficulty, a function that is commonly ascribed to this region. We used functional magnetic resonance imaging to monitor brain activity while human participants engaged in uncertain choices for prospective physical effort. Our task was designed to examine effort-based decision-making in the absence of reward and separated from choice difficulty-allowing us to investigate the brain's role in effort valuation, independent of these other factors. Participants exhibited subjectivity in their decision-making, displaying increased sensitivity to changes in subjective effort as objective effort levels increased. Analysis of blood-oxygenation-level dependent activity revealed that the ventromedial prefrontal cortex (vmPFC) encoded the subjective valuation of prospective effort, and ACC activity was best described by choice difficulty. These results provide insight into the processes responsible for decision-making regarding effort, partly dissociating the roles of vmPFC and ACC in prospective valuation of effort and choice difficulty.
行为的感知努力程度塑造了日常决策。尽管这些感知对于决策很重要，但努力的主观成本的行为和神经表现仍未得到很好的理解。虽然有许多研究表明前扣带皮层（ACC）参与了努力/奖励权衡的决策，但没有一项研究从奖励和选择难度中实验性地分离出努力评估，而这一功能通常归因于该区域。我们使用功能磁共振成像来监测人类参与者在进行不确定的身体努力选择时的大脑活动。我们的任务旨在研究没有奖励且与选择难度分离的基于努力的决策，从而使我们能够在不考虑其他因素的情况下，研究大脑在努力评估中的作用。参与者在决策中表现出主观性，随着客观努力水平的增加，对主观努力变化的敏感度增加。对血氧水平依赖活动的分析表明，腹内侧前额叶皮层（vmPFC）对预期努力的主观价值进行编码，而 ACC 活动则最好由选择难度来描述。这些结果深入了解了努力决策的过程，部分分离了 vmPFC 和 ACC 在努力和选择难度的预期评估中的作用。
