Conscious functions, such as perception and cognition, depend on coordinated brain communication, in particular between the thalamus and the brain’s surface regions, or cortex, in a variety of frequency bands ranging from 4 to 100 hertz. Propofol, the study shows, seems to bring coordination among the thalamus and cortical regions down to frequencies around just 1 hertz. Source: https://scitechdaily.com/anesthesia-doesnt-simply-turn-off-the-brain-it-dramatically-changes-and-controls-its-rhythms/