POSTERIOR PERIRHINAL CORTEX DIRECTS DORSAL CA1 COGNITIVE MAP FORMATION

The dorsal CA1 (dCA1) of hippocampus drives adaptive navigation by constructing cognitive maps that flexibly integrate spatial, task-relevant information. However, the circuit mechanisms driving this cognitive map formation during learning remain elusive. Here, using monosynaptic retrograde tracing and single-neuron projectome analysis, we identified a previously underexplored circuit from posterior perirhinal cortex (pPRH) to dCA1 that governs both the orthogonalization and abstraction of hippocampal neural dynamics. During learning of a hippocampus-dependent task, dCA1 neural activity gradually diverged between task contexts and converged to align with task goals. These representational changes closely tracked behavioral improvement over time. Notably, silencing pPRH dCA1-projecting (pPRH^dCA1) neurons abolished both learning and associated dCA1 cognitive map reorganization. Additionally, pPRH activity itself was dynamic and context-specific but lacked goal-driven convergence. These findings reveal a previously uncharacterized role for the pPRH-dCA1 circuit in orchestrating cognitive map dynamics to support flexible, goal-directed learning.