A neurometabolic signature in the frontal cortex explains individual differences in effort-based decision-making

Abstract

SummaryExploring why individuals vary in their willingness to exert effort is pivotal for understanding human motivation. Here, we utilized proton magnetic resonance spectroscopy (1H-MRS) at 7 Tesla on the dorsomedial prefrontal cortex/dorsal anterior cingulate cortex (dmPFC/dACC) and anterior insula (AI) to uncover neurometabolic factors that influence these differences. Computational modeling and machine learning revealed that a model established on dmPFC/dACC metabolites explains decisions to exert high mental effort and sensitivity to mental effort but not physical effort. Glutamate, aspartate, and lactate in dmPFC/dACC were identified as key discriminative metabolites in the dmPFC/dACC, predictive of mental effort choices, whereas AI metabolism did not relate to effort-related decisions. Notably, there was a correlation between plasma and dmPFC/dACC lactate levels, suggesting a metabolic link between peripheral and central biomarkers of effort. Our findings provide novel insights into the neurometabolic underpinnings of motivated behavior and propose novel biomarkers for mental effort-based decision-making.