MIT researchers measure the neural rhythms and spikes before, during, and after anesthesia with propofol across five regions of the brain.

via MIT

“All the cortex has to be on the same page to produce consciousness,” Miller says. “One theory about how this works is through thalamo-cortical loops that allow the cortex to synchronize. Propofol may be breaking the normal operation of those loops by hyper synchronizing them in prolonged down states. It disrupts the ability of the cortex to communicate.”

For instance, by making measurements in distinct layers of the cortex, the team found that higher-frequency “gamma” rhythms, which are normally associated with new sensory information like sights and sounds, were especially reduced in superficial layers. Lower-frequency “alpha” and “beta” waves, which Miller has shown tend to regulate the processing of the information carried by gamma rhythms, were especially reduced in deeper layers.

Read more.