Specific anterior-posterior brain-wide input patterns support specialized visuospatial processing in the mouse retrosplenial cortex

The retrosplenial cortex (RSC) is a key integrative hub involved in spatial orientation, navigation, and cognitive processes. In rodents, RSC neurons carry rich sensory and navigational signals and are interconnected with sensory, motor, thalamic, and hippocampal circuits--supporting multimodal integration. However, the circuitry that supports this integration remain unclear. Here, we combined 2-photon calcium imaging in navigating mice with brain-wide retrograde tracing to investigate how visual and positional information are represented and distributed across RSC subregions. We found a clear anterior-posterior gradient: anterior RSC neurons exhibited sharper, more reliable position tuning and preferred fast-moving visual stimuli, while posterior RSC neurons showed broader tuning and preferential responses to slower motion. These functional differences were paralleled by distinct patterns of long-range input: anterior RSC received denser projections from motor, parietal, and hippocampal-associated areas--regions implicated in position encoding--whereas posterior RSC was more strongly innervated by visual cortices. Our findings reveal that the RSC contains functionally and anatomically distinct subregions specialized for processing different visuospatial features, suggesting a modular organization that supports integration of contextual and sensory information during navigation.