Individualized decision-making driven by long-term memory retrieval in Drosophila

Decision-making is a dynamic process shaped by the accessibility of memory. The same information can lead to varying decisions both across individuals and within the same individual under different conditions. While memory retrieval plays a key role in guiding decision-making, its neural mechanisms remain largely unclear. In this study, we show that aversive olfactory long-term memory in Drosophila exhibits greater variability than short-term memory, likely due to differences in the trial-by-trial adoption of memory-guided actions. By photoactivating memory-critical mushroom body output neurons, which show individualized presynaptic terminal asymmetry and elicit idiosyncratic turning behaviors, we find a strong correlation between the adoptability of memory-driven avoidance behaviors and long-term memory performance. Furthermore, we map the downstream circuits linking memory to navigation, offering insights into how memory retrieval shapes individualized decision-making.