Brain Products MoBI Award 2026: And the winners are …

Objective: Path integration allows humans to track their position by combining self-motion cues, but these estimates drift over time. Visual landmarks can recalibrate this drift, yet how the human brain achieves this during naturalistic movement remains unclear. We aimed to characterize the behavioral and neural correlates of landmark-based correction of path integration errors in freely moving young adults, focusing on theta-band activity in the retrosplenial complex (RSC).

Approach: We combined immersive virtual reality with high-density mobile EEG (128 electrodes) while 28 healthy young adults freely walked multi-leg paths in an 80 m² room. At each stop, participants pointed toward their remembered starting position and rated their confidence; once per path, a previously seen landmark was briefly shown, allowing them to correct their pointing. EEG components were source-reconstructed and clustered around the RSC to examine theta power and phase dynamics locked to landmark presentation.

Main results: Landmarks reliably reduced pointing errors, but the correction was short-lived. We observed two peak of RSC theta activity: first 300 ms after landmark onset, and also during the corrective rotation. The first peak scaled with correction magnitude, with smaller corrections showing greater theta power and phase resetting, indicating alignment between landmark and self-motion estimates. The second peak instead tracked rotational acceleration, likely reflecting movement-related processing.

Significance: These findings offer some of the first noninvasive human evidence that RSC theta oscillations flexibly support recalibration of spatial representations, bridging rodent mechanisms with naturalistic human navigation, and showcasing the value of the MoBI approach for studying cognition in motion. Since navigation declines with healthy aging, raising disorientation and fall risk, this work also lays the groundwork for extending the paradigm to older adults, to identify early markers of navigational impairment and inform cognitivo-motor rehabilitation.