For about 175 years people have been huffing nitrous oxide for everything from vision quests to anesthetic to get plain old high. And after all that time we are only now beginning to understand how it works on our brains.
The use of general anesthesia is less than 200 years old. Before doctors were able to cause unconsciousness in patients, surgery was brutal for all involved. But despite this advancement in medicine, science still has no idea how it works.