A Unique Role for the Hippocampus in Cue Integration During Human Spatial Navigation

It is a central question in cognitive neuroscience how the brain integrates diverse sensory inputs to improve cognitive performance. This study investigated this question in the domain of human spatial navigation using high-field fMRI, a novel navigation task, and desktop virtual reality. Participants learned and retrieved spatial locations using landmarks alone (landmark condition), visual self-motion cues alone (i.e., optic flow; self-motion condition), or both cues together (combination condition). Behaviorally, participants benefited from cue integration. fMRI analyses revealed a cue integration effect in the hippocampus, which displayed positional coding only in the combination condition, and only in participants who showed behavioral evidence of cue integration. Notably, the posterior hippocampus exhibited stronger positional coding in the combination condition than in both single-cue conditions. Additionally, positional coding in the hippocampus predominantly reflected actual, rather than self-reported, locations, suggesting relatively early involvement in the cue integration process. These findings suggest that the hippocampus supports precise memory-guided navigation by integrating different spatial cues, a function beyond simple spatial representation. More broadly, this work helps reconcile the longstanding debate regarding the hippocampuss role in spatial navigation versus episodic and relational memory, facilitating a unified understanding of hippocampal function.