Evolving schema representations in orbitofrontal ensembles during learning

How do we learn about what to learn about? Specifically, how do the neural elements in our brain generalize what has been learned in one situation to recognize the common structure of – and speed learning in – other, similar situations? We know this happens; we and our mammalian kith become better at solving new problems – learning and deploying schemas (1–5) – as we go through life. However, we have little insight into this process. Here we show that using prior knowledge to facilitate learning is accompanied by the evolution of a neural schema in the orbitofrontal cortex (OFC). Single units were recorded from rats deploying a schema to learn a succession of odor sequence problems. With learning, OFC ensembles converged on a low-dimensional neural manifold across both problems and subjects; this manifold represented the common structure of the problems and its evolution accelerated across their learning. These results demonstrate the formation and use of a schema in a prefrontal brain region to support a complex cognitive operation. Our results not only reveal an important new role for the OFC in learning but also have significant implications for using ensemble analyses to tap into complex cognitive functions.