Architectural Features of the Environment Shape the Multisensory Dynamics of Peripersonal Space Remapping

The human brain continuously maps the space surrounding the body through a highly flexible system known as peripersonal space (PPS). This multisensory interface dynamically integrates visual, auditory, tactile, and proprioceptive information to guide interaction with the environment. Although PPS plasticity is well documented following tool-use, it remains unclear how the architectural properties of the surrounding environment modulate this process. Across two experiments using immersive virtual reality (VR), we investigated whether the shape of the environment affects PPS remapping after motor training with a tool. In Experiment 1, participants performed a validated visuo-tactile integration task before and after VR-based tool-use training, all within the same 16m² virtual room. Results showed a significant PPS expansion, confirming that immersive VR can reliably induce PPS plasticity. Experiment 2 tested whether environmental geometry modulates this effect: the same training was conducted in a long (2 × 8 m) and a short (8 × 2 m) virtual room. PPS expansion emerged only after training in the long-shaped environment, while no modulation was found in the short-shaped condition. These findings demonstrate that architectural features—specifically spatial openness and boundary proximity—directly influence the sensorimotor mechanisms underlying PPS plasticity. Our results highlight that the environment is not a passive background but an active component of embodied spatial representation, providing novel evidence for the integration of neurocognitive and architectural perspectives within the emerging field of neuroarchitecture.