Researchers have discovered that there’s a major difference between the hub areas in a normal brain and a comatose brain, according to the Las Angeles Times. Although previous studies have shown that the brain is a small-world network comprised of specific hub areas, a new finding shows that injury can lead the brain to a major reorganization of its traffic patterns and might give doctors a new way to determine if comatose patients are likely to recover.
Graph theory has been used to study social networks like Facebook, as well as electronic circuit engineering, but now scientists have utilized the technology to determine the connections between areas of the brain. Human brain networks are complex systems, and researchers sought to discover which parts of the brain are critical for consciousness.
Using graph theoretical methods, scientists studied the brain network topology in resting state functional MRI data from 20 healthy volunteers and 17 patients with severely impaired consciousness. Even after injury, the study revealed that patients still had brains that functioned like small-world networks and had similar graph theoretic properties to those of a normal brain. With regard to the human brain, in small-world networks, each region in the brain can be connected to another with relatively few connections.
However, the difference between a comatose brain and a healthy brain can be attributed to the hub areas, which are areas that are highly connected to other parts of the brain and help to coordinate the flow of information among them. Although the number and complexity of hubs in the brain tend to decrease over time, healthy brains remain highly connected and some brains even contain “rich clubs” because of their unusually high interconnected regions. According to the study, hubs were no longer present in comatose brains and had been taken over by other areas.
Results from the study indicate that consciousness depends on the location of hub nodes in human brain networks. The loss of connectivity to a specific brain area that supports consciousness can lead patients into a comatose state. When the brain quickly responds to a severe injury, it may reorganize itself which alters how strongly different brain areas are connected to one another.