AIM Framework glossary
Ventromedial Prefrontal Cortex (vmPFC)
Canonical definition
The ventromedial prefrontal cortex (vmPFC) is the region of the brain, located at the lower/medial aspect of the frontal lobe, that serves as the primary integration hub for common-currency valuation, receiving inputs from appetitive circuits (hypothalamus, insula), intrinsic reward systems (dopaminergic midbrain), and social-reward circuits (mirror neurons, ventral striatum), and producing a unified subjective value signal that predicts choice behaviour across diverse reward types, with the neuroimaging evidence showing that vmPFC activation magnitude scales with subjective value regardless of whether the reward is food, money, social approval, or intrinsic satisfaction.
Explanation
The vmPFC is where the AIM integration equation is physically instantiated. Levy and Glimcher's (2012) meta-analysis across hundreds of studies shows that vmPFC consistently encodes subjective value: when people evaluate options (regardless of domain) vmPFC activity correlates with "how much do I want this?" and predicts subsequent choice. Critically, the response magnitude for equivalent subjective values is similar across reward types: \$50 that feels "worth it" produces similar vmPFC activation to food that feels equally desired to social approval of similar subjective intensity. This is the neural signature of a common currency: unlike inputs (food, money, status) are converted to a unified metric (subjective value). The vmPFC's central role in integration is also why lesions to vmPFC produce trans-domain impairments: patients show disrupted decision-making across appetitive choices, gambling, and social interactions, suggesting vmPFC is a bottleneck through which all motivations pass to produce coherent action.
Epistemic status
Established Neuroscience.