The rats learned that either a tone or a light signaled the delivery of a mild electric shock. Initially, cells in the medial prefrontal cortex responded differently to the tone and to the light. However, after three weeks, the cells began to show similar responses to both stimuli.
The medial prefrontal cortex activity had thus transitioned from representing incidental details (tone versus light) to representing abstract relationships (stimulus predicts shock).
The paper Generalizable knowledge outweighs incidental details in prefrontal ensemble code over time shows how the population code of two associative memories adapt over a long time period to generalize. Maybe this could be accomplished with something as easy as Voja/PES?
Summary from the paper: