Neurons in our brain are wired like a social network, according to a new research.
Researchers at Biozentrum, University of Basel in Switzerland found that each nerve cell has links with many others, but the strongest bonds form between the few cells most similar to each other.
"We wanted to see if there are rules that explain how neurons connect in complex networks comprising millions of neurons," said Professor Thomas Mrsic-Flogel, the leader of the research team from the Biozentrum and University College London (UCL).
"It turns out that one of the rules is quite simple. Like-minded neurons are strongly coupled, while neurons that behave very differently from each other connect weakly or not at all," Mrsic-Flogel said.
The researchers focused on the visual area of the cerebral cortex, which receives information from the eye and gives rise to visual perception.
Neurons in this part of the brain respond to particular visual patterns, but it is difficult to untangle which cells are synaptically connected because there are many thousands of them densely packed (close to 100,000 per cubic millimetre).
Using a combination of high resolution imaging and sensitive electrical measurements, the researchers found that connections between nearby neurons are organised like a social network.
Sites like Facebook keep us in contact with large numbers of acquaintances, but most people have a much smaller circle of close friends, researchers said.
These are usually the friends with which we have most in common, and their opinions can be more important to us than the views of the rest, researchers said.
"Weak contacts in the brain have little impact, despite being in the majority," said Mrsic-Flogel.
"The few strong connections from neurons with similar functions exert the strongest influence on the activity of their partners. This could help them work together to amplify specific information from the outside world," added Mrsic-Flogel.
Learning may be the reason neurons share such large numbers of weak connections, researchers believe.
"If neurons need to change their behaviour, weak connections are already in place to be strengthened, perhaps ensuring rapid plasticity in the brain," said Dr Lee Cossell, one of the lead authors of the study.
The results are published in the journal Nature.
