By conducting imaging studies on volunteers under general anesthesia, researchers are developing a deeper understanding of how different areas of the brain are affected as individuals lose and regain consciousness. NPR's Fresh Air program reports on the ongoing research:
So far, researchers have learned that different drugs create different patterns in the brain, says [Emery Brown, MD, PhD, co-author of a previous study describing what researchers know and don't know about anesthesia.] For example, propofol - one of the most widely-used anesthetics - is a very potent drug and initially puts the brain into a state of excitation.
"It doesn't really cause a state of sedation or anesthesia [initially,]" says Brown. "Then what actually see next is the brain start to slow. [So first you see] a period where the brain is active and then [when you give] a higher dose, the brain starts to slow."
In contrast, the drug ketamine - which is used in conjunction with anesthesia to make certain drugs work better - puts the brain into a state of excitation even at higher doses.
Researchers say that better understanding the complex behavioral state of anesthesia could lead to improved treatments for pain, depression and sleep disorders.