The third scenario is a medical mistake, when the patient is inadvertently moved or whose position is changed and the medication is turned off.
Brain disorders show similar neurological shutdowns on EEGs as those created by anesthesia, suggesting this research may help discover new treatments.
Ketamine, for example, a drug used for anesthesia, has shown promise in smaller doses in the treatment of depression. "If we can turn the brain on and off, maybe we can also turn off chronic pain syndrome," he said.
Ambien, a widely used sleep drug, also works in some of the same ways as anesthesia, turning down internal brain activity and allowing the natural sleeping mechanism to take over.
With 40 million Americans who have some kind of insomnia and 60 million with some form of sleep disorder, the research could also provide more answers about the natural oscillations of sleep.
Brown and his colleagues described the case of a brain-injured patient in a minimally conscious state who actually recovered some functions through administration of Ambien or zolpidem.
It mirrors a common occurrence called paradoxical excitation, in which patients in the first stage of general anesthesia may move around or vocalize. The authors describe how zolpidem's suppression of the activity of a brain structure called the globus pallidus -- which usually inhibits the thalamus -- stimulates activity in the thalamus.
"Anesthesiology has long been viewed as a mystery," Brown said. "We can now muster something we can understand in neuroscientific terms."