Can people dream under anesthetics?
Kat asked Chris this question...
Chris - Almost certainly not. The reason is that when you go to sleep and you have whatís called physiological, normal sleep, this is a very organised process of brain activity. Dreaming occurs when you go through a phase of which is called REM (rapid eye movement) sleep and you can see when this happening to somebody because, if you look at them when they are sleeping. you will see their eyelids flickering because their eyeballs are moving around underneath their eyelids. If you wake someone up when theyíre doing that and ask them do you remember anything, do you recall anything, they will almost overwhelming say "I was just having a dream". And as you go through the night your dreams become longer, they become more detailed and you tend to have your best, richest and most memorable and recallable dreams right at the end of a nightís sleep. We donít know what dreams do, but theyíre very important for psychological well being. If you deprive people of restful sleep and dream sleep, then they donít feel rested the next day, they donít remember things, they canít form new memories properly, and that kind of thing. So itís probably got some kind of brain cleansing or memory consolidation role. But when you put people to sleep with an anesthetic agent, anesthetics disrupt the membranes of nerve cells and what they do is make nerve cells become less active than they should be. They increase the activity of inhibitory nerve signals in the brain and they decrease the excitation in the brain and, as a result, they basically just shut down your brain for the most part. There are some that work slightly differently but thatís the general process. And so all they do is just turn you into an unconscious individual with very low levels of brain activity, not this organised pattern of dream activity, so you do not dream when youíre under an anaesthetic, although, when youíre waking up, you may have some bizarre experiences because your brain is just beginning to kick-in and return to consciousness. And so some people do describe some rather strange memories as they wake up from an anaesthetic, but thatís not when they were actually anaesthetised.
Hallucinate maybe... but not dream. For example, administer enough ketamine and the patient will experience post-op dysphoria and hallucinations in no time.