Nitrous oxide administered at 50% for conscious sedation alters brain network connectivity in healthy adults. EEG recordings from 20 volunteers showed a steeper 1/f slope during sedation compared to baseline, indicating changes in brain network systems. Network connectivity parameters differed significantly in delta, alpha1, alpha2, and beta2 frequency bands, with the most pronounced functional distance changes in alpha1 and alpha2 bands. These alterations suggest nitrous oxide interferes with information integration in frequency bands important for cognitive processes and attention, which may relate to its sedative mechanism.
In healthy adults inhaling nitrous oxide to induce sedation while maintaining consciousness, electroencephalography revealed that functional connectivity between frontal and parietal brain regions is significantly altered. Low-frequency power increased in frontal regions during sedation and reversed after discontinuation. Granger causality analysis showed that feedback and feedforward connections changed differently across EEG frequency bands. Specifically, spectral Granger causality in the theta, alpha, and beta bands from parietal to frontal directions significantly decreased during sedation, while the reverse direction showed no significant change. This reduced parietal-to-frontal interaction may underlie the sedated state and cognitive impairment.