Hierarchical encoding of reward and effort across the cortex and basal ganglia during cost-benefit decision making

Adaptive value-guided decision-making requires weighing up the costs and benefits of pursuing an available opportunity. Though neurons across frontal cortical-basal ganglia circuits have been repeatedly shown to represent decision-related parameters, it is unclear whether and how this information is co-ordinated. To address this question, we performed large-scale single unit recordings across medial/orbital frontal cortex and basal ganglia as rats decided whether varying reward payoffs outweighed the associated physical effort costs. We found that single neurons across the circuit could encode different combinations of the canonical decision variables reward, effort and choice. Co-active cell assemblies - ensembles of neurons that repeatedly co-activated within short time windows (<25ms) within and across structures - were able to provide representations of the same decision variables through the synchronisation of individual neurons with different coding properties. Together, these findings demonstrate a hierarchical encoding structure for cost-benefit computations, where individual neurons with diverse encoding properties are coordinated into larger, lower dimensional spaces within and across brain regions to that can encode decision parameters on the millisecond timescale. ### Competing Interest Statement The authors have declared no competing interest.