Mechanisms of Economic Decisions under Sequential Offers

Abstract

Binary choices between goods are thought to take place in orbitofrontal cortex (OFC). However, current notions emerged mostly from studies where two offers were presented simultaneously, and other work suggested that choices under sequential offers rely on fundamentally different mechanisms. Here we recorded from the OFC of macaques choosing between two juices offered sequentially. Analyzing neuronal responses across time windows, we discovered different groups of neurons that closely resemble those identified under simultaneous offers, suggesting that decisions in the two modalities are formed in the same neural circuit. Building on this result, we examined four hypotheses on the decision mechanisms. OFC neurons encoded goods and values in a juice-based representation (labeled lines). Contrary to previous assessments, decisions did not involve mutual inhibition between pools of offer value cells. Instead, decisions involved mechanisms of circuit inhibition, whereby each offer value indirectly inhibits neurons encoding the opposite choice outcome. These results reconcile disparate findings and provide a unitary account for the neuronal mechanisms underlying economic decisions.