Caudate dopamine predicts cognitive effort decisions both in the lab and daily life

Making choices about whether and when to engage cognitive effort is a common feature of human everyday experience with important consequences for academic, career, and health outcomes. Yet, despite its importance, little is understood about the neurochemical mechanisms that underlie individual differences in the willingness to engage in cognitively effortful activities. To examine this question, we employed a multi-modal neuroimaging approach in which participants performed the Cognitive Effort Discounting paradigm (Cog-ED) while simultaneous PET-fMRI was acquired. We assessed both individual differences in dopamine-D2 receptor availability and brain activity during decision-making. In addition, the same participants performed a parametric working memory task (N-Back) and reported the cognitive effort associated with their daily life activities through a seven-day Ecological Momentary Assessment (EMA) protocol. The findings suggest a central role for caudate dopamine-D2 receptors in modulating cognitive effort-related motivation. People with higher caudate dopamine-D2 receptor availability had better working memory function, heightened sensitivity to effort costs, and greater modulation of brain activity during effort valuation. These laboratory findings also translated directly to daily life: higher levels of caudate dopamine-D2 receptors were associated with greater engagement in cognitively effortful activities. Together, the results suggest that how individuals determine the motivational value of cognitively effortful activities strongly depends on the dopamine system.

Weighing the costs and benefits of engaging in cognitive effort is a common feature of daily life. Nevertheless, there is little consensus about how such decisions are implemented in the human brain. This study used a cognitive effort decision-making paradigm during simultaneous PET-fMRI scanning to identify the neurochemical mechanisms engaged while participants decided whether to engage in cognitive effort. Neuroimaging measures were paired with daily life assessments of cognitive effort to directly test if individual differences in dopamine function translate to how people make daily life decisions. The results provide some of the first evidence that dopamine-D2 receptors in the dorsal striatum play an important role in cognitive effort-based decision-making, not only in the laboratory, but also in daily life.