Task-dependent neural dynamics in hippocampal CA1 during auditory and visual perceptual decision-making in rats

Perceptual decision-making involves the integration and evaluation of sensory evidence to guide behavior, yet the extent to which the hippocampus contributes to decision processes across sensory contexts remains unclear. This study combined viral neuronal tracing, touchscreen-based behavioral paradigms, and in vivo multi-electrode recordings to investigate neural activity in the hippocampal CA1 region during visual decision-making (VDM) and auditory decision-making (ADM) tasks in rats. Anterograde tracing revealed that projections from the visual (V1) and auditory (Au1) cortices to CA1 were predominantly segregated, with a smaller proportion of convergent inputs, indicating partially distinct but overlapping anatomical pathways for sensory input. Behaviorally, rats exhibited significantly longer training times and slower learning curves in ADM compared to VDM, suggesting increased cognitive demands for auditory decision-making. Electrophysiological analyses of local field potentials (LFPs) showed modality- and event-specific oscillatory dynamics, with both theta (4-10 Hz) and beta (10-20 Hz) power increases occurring at different time points for VDM and ADM tasks. At the single-neuron level, a higher proportion of delay-active neurons was observed during ADM, reflecting differential temporal recruitment of CA1 neurons across auditory and visual decision contexts. Firing pattern analyses further revealed overlapping neuronal populations engaged in both tasks alongside task-preferential subpopulations. Together, these findings indicate that hippocampal CA1 is flexibly recruited across auditory and visual perceptual decision-making tasks through partially segregated inputs and task-dependent neural dynamics.