Vision shapes neural maps of space through an ancient midbrain pathway

Mammals rely on their senses to establish their position in space. Neural activity in the hippocampus maps position, yet how sensory signals reach the hippocampus remains poorly understood. Here we uncover the visual pathways informing spatial maps in the mouse hippocampus. Hippocampal activity in mice traversing a track in alternating periods of light and darkness revealed two distinct maps, one in light and one in dark. Surprisingly, distinct maps persisted following bilateral ablations of primary visual cortex, indicating that visual signals still reach the hippocampus. Conversely, blocking the ancestral pathway linking superior colliculus to lateral visual cortex markedly reduced the difference between light and dark maps. Thus, this conserved pathway relays visual information to the hippocampus, potentially explaining residual visual navigation in cortically blind humans.