Representational Dynamics in the Hippocampus and Medial Prefrontal Cortex during Learning and Task Mastery

Abstract

While the medial prefrontal cortex (mPFC) interacts with the hippocampus to support learning and consolidation, how its neural representations evolve remains unclear. We recorded population activity from CA1 and the mPFC as rats trained on radial maze tasks over weeks. Low-dimensional mPFC manifolds generated using UMAP or PCA embeddings initially tracked session progression, showing within-session drift. As animals gained task familiarity, this temporal tracking weakened; mPFC manifolds differentiated specific arms, mirroring hippocampal representations. Arm discriminability was selectively enhanced at locations requiring spatial choices, but weakened when such demands were absent. These findings demonstrate that systems consolidation does not uniformly promote cortical generalization. Instead, the mPFC may slowly refine representations in response to specific task demands to support tailored task schemas.