Page last updated at 10:48 GMT, Tuesday, 24 March 2009

Brain waves 'foreshadow mistakes'

MEG machine
Neuroscientist Ole Jensen models the Donders Institute MEG machine

A distinct pattern of brain waves which occurs just before we make a mistake because of a lack of attention has been discovered by scientists.

The US and Dutch researchers say the discovery could help devise attention-monitoring devices for workers such as air traffic control operators.

It may also help aid new treatments for children with attention deficit hyperactivity disorder (ADHD).

The study appears online in the journal Human Brain Mapping.

Say you're sitting in a room and you close your eyes - that causes a huge alpha rhythm to rev up in the back of your head
Dr Ali Mazaheri
University of California, Davis

The researchers, from the University of California, Davis, and the Donders Institute in the Netherlands, recruited 14 students to take part in the study, monitoring their brain activity using a recording technique called magnetoencephalography (MEG).

Each student was asked to take part in monotonous test in which a random number from one to nine flashed on a screen every two seconds, and they were asked to tap a button as soon as any number except five appeared.

The test was so boring that even when a five showed up, the subjects spontaneously hit the button an average of 40% of the time.

The researchers found that about a second before these errors were committed, brain waves in two regions were stronger than when the subjects correctly refrained from hitting the button.

In the back of the head (the occipital region), alpha wave activity was about 25% stronger, and in the middle region, the sensorimotor cortex, there was a corresponding increase in the brain's mu wave activity.

Running on idle

Researcher Dr Ali Mazaheri said: "The alpha and mu rhythms are what happen when the brain runs on idle.

"Say you're sitting in a room and you close your eyes. That causes a huge alpha rhythm to rev up in the back of your head.

"But the second you open your eyes, it drops dramatically, because now you're looking at things and your neurons have visual input to process."

The team also found that errors triggered immediate changes in wave activity in the front region of the brain, which appeared to drive down alpha activity in the rear region.

Dr Mazaheri said: "It looks as if the brain is saying, 'Pay attention!' and then reducing the likelihood of another mistake."

He said it should be possible to develop a wireless monitoring device to read an air traffic controller's brain waves, and trigger an alert when alpha activity begins regularly to exceed a threshold level.

A similar approach could be used to determine waning attention in children with ADHD.

"That can help us design therapies as well as evaluate the efficacy of various treatments, whether it's training or drugs."

Professor Nilli Lavie, of the Institute of Neurology at University College London, said in increase in alpha brain wave activity was often associated with sleepiness.

She said the study was interesting, but finding a practical application could prove difficult.

She said: "The best way to tackle the problem of monotonous tasks is to design the task to make it more visually interesting so it is easier to sustain attention."

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