Electrical Signal in Brain Seems to Warn of 'Mistakes'
Finding may help in kids with ADHD, workers under stress
MONDAY, March 23, 2009 (HealthDay News) -- A distinct electric signature in the brain indicates when someone is about to make a mistake, say researchers who scanned the brain waves of volunteers as they worked on attention-demanding tasks.
The American and Dutch researchers said their findings could have a wide range of applications, such as developing new ways to help children cope with attention-deficit/hyperactivity disorder (ADHD) or creating monitoring devices that alert air traffic controllers when their attention is wavering.
The study included 14 university students who did a test called the "sustained attention response task," which is used to evaluate brain damage, ADHD and other neurological disorders. Participants watched a computer screen for an hour as a random number from one to nine flashed on the screen every two seconds. Participants tapped a button as soon as any number except five appeared on the screen.
Due to the monotony of the test, participants hit the button about 40 percent of the time when they saw the number five, said Ali Mazaheri, a research fellow at the Center for Mind and Brain at the University of California, Davis.
As the participants did the test, their brain wave activity was recorded using magnetoencephalography, which is more sensitive than the electroencephalography, or EEG, commonly used in hospitals to detect seizures. The results showed that brain waves in two regions of the brain -- the occipital region and the sensorimotor cortex -- were about 25 percent stronger about a second before participants made an error.
The increases involved alpha waves in the occipital region, located in the back of the brain, and mu waves in the sensorimotor cortex, located in the middle of the brain.
In addition, the researchers found that errors triggered changes in wave activity in the front region of the brain, which seemed to reduce alpha wave activity in the occipital region.
"It looks like the brain is saying, 'Pay attention!' and then reducing the likelihood of another mistake," Mazaheri said in a news release from the university.
The findings, published online March 23 in the journal Human Brain Mapping, could someday benefit children with ADHD.
"Instead of watching behavior -- which is an imprecise measure of attention -- we can monitor these alpha waves, which tell us that attention is waning," Mazaheri said. "And that can help us design therapies as well as evaluate the efficacy of various treatments, whether it's training or drugs."
The U.S. National Institute of Mental Health has more about ADHD.