Is a scientific definition of consciousness possible?
UCLA psychologists have used brain-imaging techniques to study what happens to the human brain when it slips into unconsciousness.
Their research, published in the online open-access journal PLOS Computational Biology, is an initial step toward developing a scientific definition of consciousness, the researchers say.
“In terms of brain function, the difference between being conscious and unconscious is a bit like the difference between driving from Los Angeles to New York in a straight line versus having to cover the same route hopping on and off several buses that force you to take a ‘zig-zag’ route and stop in several places,” said
Lead study author Martin Monti, an assistant professor of psychology and neurosurgery at UCLA, and his colleagues used functional magnetic resonance imaging (fMRI) to study how the flow of information in the brains of 12 healthy volunteers changed as they lost consciousness under anesthesia with propofol.
The participants ranged in age from 18 to 31 and were evenly divided between men and women.
The psychologists analyzed the “network properties” of the subjects’ brains using a branch of mathematics known as graph theory, which is often used to study air-traffic patterns, information on the Internet and social groups, among other topics.
“It turns out that when we lose consciousness, the communication among areas of the brain becomes extremely inefficient, as if suddenly each area of the brain became very distant from every other, making it difficult for information to travel from one place to another,” Monti said.
The finding shows that consciousness does not “live” in a particular place in our brain but rather “arises from the mode in which billions of neurons communicate with one another,”