We’ve all experienced lapses in attention. It can happen while we’re driving, folding laundry, making dinner, or doing something else monotonous. Thankfully, our mental vacations normally result in harmless mistakes, but sometimes the consequences can be serious. Driving accidents, laboratory disasters, and other catastrophes often occur when people stop concentrating on the task at hand.
Neuroscientists are interested in figuring out what happens in the brain when people get distracted, especially before it occurs, as being able to predict the occurrence of errors from a lack of concentration could be useful in preventing accidents. Ali Mazaheri from the University of California at Davis and three researchers from Radboud University Nijmegen in the Netherlands correlated brain activity with the way volunteers performed a dull and repetitive assignment. From their study, they found that the brain does give clues before it wanders.
In their experiment, Mazaheri and his colleagues asked 14 volunteers to look at a screen that flashed a number between 1 and 9. The volunteers were asked to press a button for every number except “5.” Since they were shown “5” irregularly and the task was pretty boring, they should be expected to lose focus. Throughout the experiment, the authors used MEG (Magnetoencephalography) to monitor the oscillations in brain activity of each volunteer at characteristic frequencies. MEG is a method for brain imaging that measures the magnetic fields resulting from the electrical currents flowing through neurons.
The experimental setup succeeded in lulling the volunteers to wrongfully press the button for “5”—the error rate was about 40 percent. The researchers discovered two distinguishing differences in the brain prior to the appearance of the number “5” when comparing occurrences of wrong button pushes with those of correct responses. They found increased alpha wave activity in the occipital region and mu wave activity in the sensorimotor cortex.
Alpha waves are associated with periods of idleness in the visual cortex, while mu waves represent an idle state for the motor cortex. Movement, or even the intention to do something, will reduce those waves. Thus, the authors reason that the amplified alpha activity caused volunteers to need more time to perceive the stimulus “5,” and then the increased mu activity made it harder for them to make a change in their motor response. In essence, their brains were in an inactive state and were less capable of reacting to a different stimulus.
The authors see many uses for their findings, such as the development of wireless devices to monitor brain activity for attentiveness. They write that “activity in the alpha band can be applied online to predict if subjects are in a state where errors are more likely to be committed.” For example, if someone's attention begins to drift, some form of a warning can be given to refocus it before an accident occurs.
Besides preventing mishaps, monitoring brain activity for attention can also help people with ADHD. It would be an improvement over current methods of watching for behavior changes to measure how well treatments are working. While the applications are numerous, further experiments are necessary to verify the accuracy of using alpha and mu activity to predict attention. It will be important to see whether this same finding holds up when tested in a diverse range of tasks.
Human Brain Mapping, 2009. DOI: 10.1002/hbm.20763