Nitrous oxide reduces resting total brain wave power, especially delta waves at frontal-vertex sites, in healthy men. After inhalation stops, frontal theta power increases above baseline. Unlike other anesthetics such as propofol and sevoflurane, nitrous oxide does not shift slow wave activity to the front of the brain, challenging a single mechanism for loss of consciousness based on EEG patterns.
Nitrous oxide (N2O), an NMDA receptor antagonist, reduces parietal network functional connectivity by about 50% and frontal network connectivity by about 10%, as measured by EEG. Parietal reductions were detected only with a surface Laplacian derivation, indicating superficial cortical networks are most affected, while frontal reductions were detected with a common-reference derivation, suggesting widespread perturbations. These findings support the idea that different anesthetic agents may produce similar final network changes underlying reduced consciousness.