Alpha wave blocks your mind for distraction, but not continuously

October 9, 2012, Radboud University Nijmegen

Alpha waves were long ignored, but gained interest of brain researchers recently. Electrical activity of groups of brain cells results in brain waves with different amplitudes. The so called alpha wave, a slow brain wave with a cycle of 100 milliseconds seems to play a key role in suppressing irrelevant brain activity. The current hypothesis is that this alpha wave is associated with pulses of inhibition (every 100 ms) in the brain.

Mathilde Bonnefond and Ole Jensen (Radboud University Nijmegen, The Netherlands) discovered that when distracting information can be anticipated in time there is an increase of the power of this alpha wave just before the distracter. Furthermore, the brain is able to precisely control the alpha wave so that the pulse of inhibition is maximal when the distracter appears. Indeed, between pulses of inhibition, there is still a window where the brain is excitable. 'It is like briefly opening a door to look what's happening outside. This enables us to detect an unexpected but important or dangerous event. But to avoid to be distracted by completely irrelevant information, it is better if the inhibition is active when a distracter is presented. It could be seen as a mechanism slamming the door of the brain on intruders'. The results are published by the scientific journal at October 4.

The researchers designed an experiment in which timing of suppressing information was crucial for performance. The subjects were trained to do a in a strict rhythm. Those subjects that were able to synchronize their alpha activity with the rhythm in which irrelevant distracters were presented had the highest score on the task. This is an unconscious process by the way. The researchers presume that the ability to adjust alpha activity to the expected distracting information might play a role when we actively sample the environment.

Experimental set up

Eighteen volunteers were tested with a non-invasive brain-wave recording technique, magnetoencephalography (MEG). The volunteers had to do a working memory task (i.e. maintaining some information in their memory over a period of a few seconds) during which the waves generated by their brain were recorded. In each trial, they had to remember four letters presented on a screen every one second. After that, a distracter was briefly presented. The distracter was either another letter (strong distracter) or a symbol (weak distracter). Participants were asked to ignore the distracter (control experiments were ran to make sure they followed the instructions). One second after the distracter, another letter was briefly presented and the participants had to determine whether this letter was similar to one of the four letters they had to remember earlier

The experiment consisted of blocks of trials with only one type of distracter (strong or weak) presented after the letters to remember in each trial. Very importantly, the time before the distracter was always the same so that the subjects could anticipate the timing of presentation of the distracter. The were stronger before the strong distracters than before the weak distracters, confirming that these waves close our brain for distracting information.

Explore further: Meditation may help the brain 'turn down the volume' on distractions

More information: Bonnefond et al.: 'Alpha oscillations serve to protect working memory maintenance against anticipated distracters', Current Biology, print issue October 23, 2012, online October 4

Related Stories

Meditation may help the brain 'turn down the volume' on distractions

April 21, 2011
The positive effects of mindfulness meditation on pain and working memory may result from an improved ability to regulate a crucial brain wave called the alpha rhythm. This rhythm is thought to "turn down the volume" on distracting ...

How do we split our attention?

December 21, 2011
McGill's Cognitive Neurophysiology Lab team finds that we are natural-born multi-taskers.

Noisy surroundings take toll on short-term memory

September 6, 2012
Have you ever noticed how tiresome it can be to follow a conversation at a noisy party? Rest assured: this is not necessarily due to bad hearing – although that might make things worse. Scientists at the Max Planck Institute ...

The beat goes in the brain: Visual system can be entrained to future events

August 28, 2012
(Medical Xpress)—Like a melody that keeps playing in your head even after the music stops, researchers at the University of Illinois's Beckman Institute have shown that the beat goes on when it comes to the human visual ...

The benefits of meditation: Neuroscientists explain why the practice helps tune out distractions and relieve pain

May 5, 2011
Studies have shown that meditating regularly can help relieve symptoms in people who suffer from chronic pain, but the neural mechanisms underlying the relief were unclear. Now, MIT and Harvard researchers have found a possible ...

Recommended for you

Your brain responses to music reveal if you're a musician or not

January 23, 2018
How your brain responds to music listening can reveal whether you have received musical training, according to new Nordic research conducted in Finland (University of Jyväskylä and AMI Center) and Denmark (Aarhus University).

New neuron-like cells allow investigation into synthesis of vital cellular components

January 22, 2018
Neuron-like cells created from a readily available cell line have allowed researchers to investigate how the human brain makes a metabolic building block essential for the survival of all living organisms. A team led by researchers ...

Finding unravels nature of cognitive inflexibility in fragile X syndrome

January 22, 2018
Mice with the genetic defect that causes fragile X syndrome (FXS) learn and remember normally, but show an inability to learn new information that contradicts what they initially learned, shows a new study by a team of neuroscientists. ...

Epilepsy linked to brain volume and thickness differences

January 22, 2018
Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research led by UCL and the Keck School of Medicine of USC.

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

gmurphy
not rated yet Oct 10, 2012
One would think that the natural environment would not contain much by way of such rigidly defined cycles.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.