A Dual-Ensemble Model of Infralimbic Cortex Function in Behavioural Flexibility
The infralimbic cortex (IL) has been described as both facilitator and terminator of reward-seeking, yet both functions appear mutually exclusive. We reconcile this discrepancy by proposing a dual-ensemble model: one for action-outcome prediction and another for prediction correction. Using longitudinal miniscope imaging in rats, we show that during training, the action-outcome predictor ensemble sharpens its activity by suppressing the majority of the IL neuronal population. As contingencies stabilize, entropy decreases, reflecting a refined predictive model. During extinction, the prediction correction ensemble activates in response to reward omission. A computational simulation based on these two ensembles successfully recapitulated our experimental results. This framework reconciles conflicting models, where IL manipulation can either accelerate or abolish extinction by demonstrating that IL activity dynamically encodes predictive accuracy. Our findings indicate that IL functions as an action-outcome predictor that elegantly guides behavioural flexibility.