Foetuses` brains run on idle mode before birth

A new study finds that the brain remains idle till the time a foetus reaches full-term inside the mother`s womb.

London: It`s known that our brains buzz with activity even though we are sleeping. Now a new study has found that this brain process develops by the time a foetus reaches full-term inside the mother`s womb.
According to scientists, "resting state activity" is what the brain engages in when it isn`t working on a particular task. The neurons that carry out this action are in networks
all over the brain, from visual areas to motor areas to areas involved in attention and abstract thinking.

One of these networks, the default mode network, engages when people are in a state of wakeful rest which is linked to daydreaming and introspection.

Now, scientists at the Imperial College London found that the default mode network is fully operational by birth, which suggests that its role is more than for introspection alone.

"Either babies are lying there introspecting -- which is possible, although we can`t remember it -- or else this theory is a bit wrong," study researcher David Edwards, a professor of neonatal medicine, told LiveScience.

For their research, Edwards and his colleagues used functional magnetic resonance imaging (fMRI) to see changes in blood flow throughout the infants brains. Increased blood flow brings more oxygen and correlates with brain activity.

They carried out the brain scans on 70 healthy infants who were born after 29 to 43 weeks of development and found that the resting state networks were completely developed in full-term babies.

Babies born at 30 weeks development had incomplete but recognisable fragments of the networks, which suggests that resting state networks in infants develop within the last 10
weeks of pregnancy. Once a foetus is 40 weeks old, its network looks much like an adult`s, the researchers found.

Previous studies had found fragments of these networks, but the new research used sensitive methods to uncover the entire system, they said.

The findings suggest that resting state networks are less involved with conscious action and thoughts than had been believed, Edwards said.

"They`re more fundamental than has previously been thought, because they don`t need to be related to any cognitive aspect," Edwards said. "They`re very fundamental bits of brain
activity and therefore very powerful to help us understand what the brain is really doing."

The researchers are now studying infants with disrupted resting state networks to find out if the disruption affects the babies` development.

The new study is published in the journal Proceedings of the National Academy of Sciences.