Researchers at the University of Turku say that they have found that the insular cortex of babies’ brains – the area that regulates human emotion – is activated by touch.
In MRI tests of 13 babies, scientists examined the influence of touch on the brains of babies aged about one month.
When the infants fell asleep after nursing, researchers stroked their right arms with a soft brush. They then analysed the results to determine which areas of their brains reacted to the caresses.
Story continues after image
The researchers found that separate areas of the brain responded to stroking on different parts of the body and that a certain type of nerve cell is responsible for relaying social contact. Professor of Integrative Neuroscience and Psychiatry Hasse Karlsson said that each part of the body is associated with an area of the brain. So it the hand is touched, a specific part of the brain is activated.
Touch-sensitive nerve cells virtually active from birth
This mechanism works the same way in young babies but researchers found that another area, the insular cortex, which also regulates emotional experiences, is also affected.
The Finnish researchers collaborated with colleagues from the University of Gothenburg and found specific nerve cells in the skin that relay signals from the slow stroking. These nerve cells were activated when scientists stroked areas of the skin with hair and where the speed of the action was between three and 10 centimetres per second.
It was previously not known at what stage these kinds of nerve cells become functional. According to Karlsson the research suggests that in practice, the cells are active very soon after birth.
"This provides a bit more information about why touching and especially stroking children is important. It appears to activate the parts of the brain that are associated with regulating emotion and especially with achieving a positive emotional state," he added.
Story continues after photo
"Almost all animal species lick or groom their young. The speed of licking or grooming is usually very similar to what we did here. In other words, this could be a kind of evolutionary system for calming [infants] or achieving a positive emotional state that has remained in humans."
Babies to be observed until adulthood
Imaging the babies’ brains is part of a broader FinnBrain research project that aims to unravel the interplay between environment and heredity influences in a child’s development.
The expansive programme began in 2010, involves more than 4,000 families and will track the children from the earliest stages of life until adulthood.
A smaller segment of the study seeks to map the children’s brain structure and function.
"We are especially interested in whether or not the action of the brain during the stroking is in some way linked to other aspects of a child’s development later on," Karlsson said.
The goal is to get a better grasp of the factors that affect neurological development in children and possible later illnesses or emotional disturbances.
According to Karlsson, what makes the findings original is that the research subjects are such young infants and that instead of cognitive development, the research focused on the development on emotional development and self-regulation.