Brain fatigue analysis from virtual reality visual stimulation based on Granger Causality

•Watching VR videos over long durations can lead to relatively more brain fatigue.•The GC and CD was reduced throughout the brain in fatigue, and the VR results showed more significant changes than the TP results.•A decrease in Eg and an increase in L indicates that the ability to convey and integrate information has been weakened because of the brain fatigue after watching the videos.•The distribution of CF before and after watching the videos indicate that information flows out of the parietal and occipital areas and flows into the frontal and temporal areas. Owing to the wide applications of virtual reality (VR) technology and VR devices, the problem of brain fatigue caused by prolonged VR use has attracted significant attention. To analyze the effect of VR use on brain fatigue, in this study, electroencephalogram (EEG) signals were acquired synchronously while 16 healthy subjects watched the VR videos. Meanwhile, the subjects also watched similar types of videos on a traditional plane (TP) displayer at different times for comparison, hoping to find out a neurometric indicator able to detect fatigue caused by VR in terms of brain networks. Two questionnaires were administered to the subjects to evaluate their state of brain fatigue. In addition, the brain networks were constructed using EEG by Granger Causality (GC), and the characteristic parameters of brain networks while watching the videos on the TP and VR devices were compared. Our results indicate a significant difference between the two cases (i.e., before and after watching the videos) in terms of characteristic path length, global efficiency, causal density, and causal flow in the frequency domain of the brain effective network, and this difference was more pronounced in the case of the subjects watching the VR video, which indicates higher brain fatigue in those subjects. This study provides a theoretical basis and experimental reference for analyzing and evaluating brain fatigue induced by visual VR experience.