Learning-Dependent Shift from Right to Left CA3 Input Dominance Shapes the Evolution of Right CA1 Spatial Maps.

ABSTRACT: CA1 place fields support spatial maps critical for memory, yet how bilateral CA3 inputs shape these maps during learning remains unclear. Using two-photon calcium imaging and optogenetic inhibition in head-fixed mice navigating a virtual track, we examined left and right CA3 projections to right CA1 (CA1_R) as animals familiarized to a novel environment. CA1_R maps were initially inaccurate but stabilized after ~10 laps, defining an early-phase of map refinement followed by a late-phase of stability. During the early-phase, right CA3 inputs predominantly drove refinement, whereas left CA3 inputs controlled stability later. These effects arose at the single-cell level, with right CA3 inputs driving high-amplitude, reliable fields early and left inputs supporting reliable fields later. Axonal recordings revealed a matching shift: right CA3 axons showed greater place-field activity and reliability early, whereas left CA3 axons became more reliable later. Thus, CA3 input dominance transitions from right to left, coordinating CA1_R map refinement and stabilization.

SUBMITTER: Jiang A 

PROVIDER: S-EPMC12636601 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature