Neuronal representation of the decisional reference point in monkeys

The reward reference point serves as a hidden benchmark for evaluating options in decision-making. Despite extensive behavioral evidence for reference-dependence, no neural representation of the reference point has been discovered. We analyzed single neuron activity from macaque monkeys performing a decision-making task designed to orthogonalize objective reward values from the reference point. Regression analyses of neuronal activity across six frontal brain regions identified a robust neural representation of the reference point in the ventral bank of anterior cingulate cortex (vbACC). Activity in the dorsal bank of anterior cingulate cortex and the dorsolateral prefrontal cortex, in contrast, encoded the reference-dependent subjective values of the rewards offered or obtained on each trial. The temporal dynamics of these signals and connections between these regions suggest a dedicated neural circuit implementing reference-dependent reward encoding, with the vbACC serving as the reference point signal source modulating activity in other frontal value-encoding areas.