PT - JOURNAL ARTICLE AU - Silvia Maggi AU - Mark D. Humphries TI - Independent population coding of the past and the present in prefrontal cortex during learning AID - 10.1101/668962 DP - 2020 Jan 01 TA - bioRxiv PG - 668962 4099 - http://biorxiv.org/content/early/2020/08/12/668962.short 4100 - http://biorxiv.org/content/early/2020/08/12/668962.full AB - Medial prefrontal cortex (mPfC) plays a role in present behaviour and short-term memory. Unknown is whether the present and the past are represented in the same mPfC neural population and, if so, how the two representations do not interfere. Analysing mPfC population activity of rats learning rules in a Y-maze, we find population activity switches from encoding the present to encoding the past of the same events after reaching the arm-end. We show the switch is driven by population activity rotating to orthogonal axes, and the population code of the present and not the past reactivates in subsequent sleep, confirming these axes were independently accessible. Our results suggest mPfC solves the interference problem by encoding the past and present on independent axes of activity in the same population, and support a model of the past and present encoding having independent functional roles, respectively contributing to on-line learning and off-line consolidation.Competing Interest StatementThe authors have declared no competing interest.