How anesthesia works is “really, really simple”–at least according to anesthesiologist, neuroscientist and statistician Emery Brown. He is a professor of medical engineering and computational neuroscience at MIT, and an anesthesiologist at Massachusetts General Hospital. Brown (the professor) came to speak at Brown (the university) on Thursday at the Presidential Colloquium Series ThinkingOut Loud (again, what is with this formatting?). Dr. Brown described how general anesthesia works and how it relates to our understanding of consciousness.
Anesthesia is a drug-induced state that is comprised of unconsciousness, amnesia, analgesia (the inability to feel pain) and akinesia (the inability to move). All of these also happen to be the symptoms of death–luckily, the final definition an anesthesia state is stability and control, allowing the state to be reversible. Being put under anesthesia is one of the most safe and and common clinical procedures.
Your brain activity can be tracked with EEG scans that record oscillations in brain signals. Slow oscillations are associated with a loss of consciousness under anesthesia.
When patients emerge from anesthesia, they first respond to the most salient stimulus, their name. Then, they respond to random words–such as “book chair,” in the study done on this topic–and then to tones. During this process, brain rhythms move from the front of the brain to the back, which can be seen in EEG scans from various parts of the brain. This process is known as anteriorization, and is key to determining the neural effects of anesthesia.