The brain’s concentration channel...
To successfully concentrate, the brain needs to “turn off” a group of neurones, which function all the time, as this network can interfere with the attention if it’s not sufficiently deactivated.
A French research team from Lyon has shown that the brain switches constantly between the “attention network” and its “default network” – and it’s this attention network that is needed when you have to concentrate.
The brain’s attention network and default network
When we concentrate on what’s going on around us, certain parts of the brain become active: this is the network which controls attention. At the same time, other regions interrupt these neurones’ activity, as these other neurones normally control attention, pushing it towards the outside world. These regions form a network called the “default network”, due to the fact that, for a long time, it appeared to activate when the brain had nothing in particular to do.
After 10 years of research using neuroimaging, this mysterious network, (“the dark matter of the brain” according to one of its discoverers, Marcus Raichle), can be seen as being associated with numerous phenomena, both intimate and private, in your psychological life, including the perception of yourself, evocation of memories, your imagination and thoughts...
The brain is constantly active
Now, a study carried out by a team at the Lyon Centre of Research into Neurosciences has revealed how this network in the brain interferes with our attention spans, by measuring, for the first time, the activity per millisecond of these neurones in the default network in the human brain, thanks to collaboration with Philippe Kahane’s epilepsy service in Grenoble.
The results were conclusive and showed that when we search for an object around us, the neurones in this default network interrupt their activity. But this interruption only lasts as long as the search; as soon as the object is found, and in barely a tenth of a second, the default network begins its activity once more. If this default network sometimes does not deactivate sufficiently, it will take longer to find whatever you are looking for.
Two conflicting networks in the brain
When you are looking attentively for something around you, the certain cerebral areas will be activated; but at the same time, it is also necessary for other areas to be deactivated.
These results attest that there is a fierce competition taking place at the centre of the brain over our “attention resources”. As soon as they are not used for active analysis of the surroundings, or sensory environment, they are instantaneously redirected towards more internal thought processes.
It seems that the brain never rests without anything to do, not even for a tenth of a second.
- Inserm press release, October 2011
- “Transient Suppression of Broadband Gamma Power in the Default-Mode Network Is Correlated with Task Complexity and Subject Performance,” Ossandon T, Jerbi K, Vidal J, Bayle D, Henaff MA, Jung J, Minotti L, Bertrand O, Kahane P, and Lachaux JP - The Journal of Neuroscience, October 2011, 31(41): 14521-14530
Copyright © 2012 Doctissimo
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