Temporal dynamics of frontoparietal processing during personal space intrusion

Understanding the neural basis of personal space (PS) is crucial for elucidating the mechanisms of social behavior. We investigated EEG responses in healthy adults viewing approaching faces designed to simulate intrusions into PS. Approaching faces elicited stronger right N170 modulation than static faces, with weaker effects for non-face objects. Time-frequency analyses revealed early alpha-power decreases over the frontal region of interest (ROI), followed by later alpha-power decreases and gamma-power increases over the parietal ROI, selectively for approaching faces. Motion information was decoded earlier in the parietal ROI than in the frontal ROI, with the frontal ROI showing face-specific sensitivity. We further demonstrated sustained parietal-to-frontal low-gamma feedforward signaling during face approach, with late frontal-to-parietal alpha-band feedback. Crucially, feedforward signaling predicted individual PS size. Together, these findings suggest that coordinated frontoparietal interactions may facilitate rapid detection and continuous monitoring of PS intrusions, providing a mechanistic framework for adaptive social defense.