Researchers Say They've Found a Better Way to Measure Consciousness
Research on brain activity and consciousness could lead to better ways to measure patients undergoing anesthesia.
A team at the University of Wisconsin—Madison measured brain activity in about 1,000 neurons near 100 sites in the brains of monkeys under anesthesia as well as when roused from anesthesia through electrical stimulation. They also monitored them during resting wakefulness and light sleep.
“What has been shown for 100 years in an unconscious state like sleep are these slow waves of electrical activity in the brain,” says Yuri Saalmann, a psychology and neuroscience professor at the university. “But those may not be the right signals to tap into. Under a number of conditions — with different anesthetic drugs, in people that are suffering from a coma or with brain damage or other clinical situations — there can be high-frequency activity as well.”
They sorted the data to determine which parts of the brain and which activity corresponded the most with consciousness. The results pointed away from the frontal cortex, the region usually monitored for patients under anesthesia.
“In the clinic now, they may put electrodes on the patient’s forehead,” says Mohsen Afrasiabi, the other lead author of the study. “We propose that the back of the head is a more important place for those electrodes, because we’ve learned the back of the brain and the deep brain areas are more predictive of state of consciousness than the front.”
The research team is part of a collaboration supported by the National Science Foundation that’s working on applying its findings, possibly to obtain more accurate measurements for patients under anesthesia or help patients in comas.
“Beyond just detecting the state of consciousness, these ideas could improve therapeutic outcomes from people with consciousness disorders,” says Saalmann, whose work is also supported by the National Institutes of Health. “We could use what we’ve learned to optimize electrical patterns through precise brain stimulation and help people who are, say, in a coma maintain a continuous level of consciousness.”