inthenews, July 7, 2008

When mothers see their baby smiling it creates a ‘natural high’, new research has discovered.

The smile creates activity in the reward centres of the brain as well as areas associated with emotion processing, cognition and motor/behavioural outputs.

These areas have been activated in previous experiments associated with drug addiction.

“It may be that seeing your own baby’s smiling face is like a ‘natural high’,” said Dr Lane Strathearn.

He and his colleagues from the Baylor College of Medicine, US, studied 28 first-time mothers with babies aged between five and ten months.

They were asked to watch photos of their own babies and other infants while they were in a functional magnetic resonance imaging scanner (brain scanner).

This machine measures blood flow in the brain, with scans showing ‘lit up’ areas where activity is taking place.

In some of the photos, babies were smiling or happy. In others they were sad, and in some they had neutral expressions.

They found that when the mothers saw their own infants’ faces, key areas of the brain associated with reward lit up during the scans.

The strength of the reaction depended on the baby’s facial expression, with the strongest activation from smiling faces.

There was less effect from pictures of their babies with sad or neutral expressions and the researchers found little difference in the reaction of the mothers’ brains to their own babies’ crying face compared to that of an unknown child.

They argue that their findings, published in the journal Pediatrics, have important implications for understanding the bond between mothers and children and how it can go wrong.

“The relationship between mothers and infants is critical for child development,” said Dr Strathearn.

“For whatever reason, in some cases, that relationship doesn’t develop normally. Neglect and abuse can result, with devastating effects on a child’s development.

“Understanding how a mother responds uniquely to her own infant, when smiling or crying, may be the first step in understanding the neural basis of mother–infant attachment,” he added.