Theta activity in the RSC anchors space to the body cardinal axes

Understanding human navigation in ecological, freely moving conditions requires uncovering how the brain anchors directional representations to the body’s orientation. Using high-density mobile electroencephalography and immersive virtual reality during goal-directed whole-body rotations, we found that theta bursts reconstructed in the retrosplenial complex (RSC) encode both acceleration and alignment with the body’s principal axes. Crucially, this body-axis–anchored neural signal emerged only during goal-directed rotations, and its strength correlated with individual navigation performance, suggesting an adaptive mechanism which provides a stable egocentric scaffold for orientation. These results provide compelling evidence for a self-motion-gated, body-centered reference frame that supports efficient navigation, and bridge the gap between static neuroimaging findings in humans and rodent research on RSC geometry codes. Overall, our findings advance an embodied, mechanistic account of human navigation, opening new avenues for investigating brain dynamics in naturalistic, movement-rich settings using non-invasive neural recordings.