Hierarchy in the mouse frontal cortex in mnemonic olfactory decision-making

The prefrontal cortex plays a critical role in integrating the memory of a recent experience to guide context-dependent decisions, yet how its subregions may map onto the steps of decision formation remains poorly understood. Using an olfactory delayed non-match-to- sample task with graded stimulus similarity in head-fixed mice, we examined how decisions emerge when a current sensory event and a memory of a recent event must be compared. With high-density extracellular recordings across the frontal cortex, we characterized odor-specific delay activity and decision-related signals. We found a topographical gradient from regions enriched in sensory representations to those dominated by choice-related activity, with intermediate regions showing choice modulations that retain stimulus sensitivity. Notably, the secondary motor cortex showed minimal sensory coding, suggesting that areas engaged by mnemonic decision-making differ from simpler, stimulus-response decision-making in the rodent brain. Together, these results indicate a functional organization that may correspond to sequential sub-steps in decision formation and a hierarchical structure within prefrontal circuits.