Dissociable roles of cortical excitation-inhibition balance during patch-leaving versus value-guided decisions

In a dynamic world, it is essential to decide when to leave an exploited resource. Such patch-leaving decisions involve balancing the cost of moving against the gain expected from the alternative patch. This contrasts with value-guided decisions that typically involve maximizing reward by selecting the current best option. Patterns of neuronal activity pertaining to patch-leaving decisions have been reported in dorsal anterior cingulate cortex (dACC), whereas competition via mutual inhibition in ventromedial prefrontal cortex (vmPFC) is thought to underlie value-guided choice. Here, we show that the balance between cortical excitation and inhibition (E/I balance), measured by the ratio of GABA and glutamate concentrations, plays a dissociable role for the two kinds of decisions. Patch-leaving decision behaviour relates to E/I balance in dACC. In contrast, value-guided decision-making relates to E/I balance in vmPFC. These results support mechanistic accounts of value-guided choice and provide evidence for a role of dACC E/I balance in patch-leaving decisions. Here, the authors show that the balance between excitation and inhibition in two cortical areas is differentially related to maximizing immediate rewards, and to weighting the cost against long-term gains of moving to a new environment.

Automated summary

The balance between excitation and inhibition in the dorsal anterior cingulate cortex plays a role in patch-leaving decisions, while the same balance in the ventromedial prefrontal cortex is related to value-guided decision-making. This differential relationship highlights the importance of weighing immediate rewards against long-term gains in different cortical areas.