Dissociable Roles of Ventromedial Prefrontal Cortex and Anterior Cingulate in Subjective Valuation of Prospective Effort

Abstract

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 (fMRI) 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 (BOLD) activity revealed that the ventromedial prefrontal cortex (vmPFC) encoded the subjective valuation of prospective effort and ACC encoded choice difficulty. These results provide insight into the processes responsible for decision-making regarding effort, dissociating the roles of vmPFC and ACC in prospective valuation of effort and choice difficulty.

The neural basis of effort valuation: A meta-analysis of functional magnetic resonance imaging studies

“…Another situation that requires cognitive control is difficult decision-making when two simultaneously presented options have similar net value (Chong et al, 2017;Hunt et al, 2012;Klein-Flugge et al, 2016;Massar et al, 2015;Shenhav et al, 2013). Indeed, studies that have independently manipulated net value and decision difficulty showed that these frontal regions, particularly the dorsal ACC, specifically tracked decision difficulty (Hogan et al, 2017;Westbrook et al, 2019) while, in contrast, the vmPFC uniquely tracked net value (Westbrook et al, 2019). Taken together, these findings suggest that this distinct frontal network is recruited more specifically for cognitive control, such as response planning and option comparison, and that effortrelated value integration is still processed in the core valuation network (e.g., vmPFC and VS) that have been identified in other cost domains.…”