UQ medical graduate and US-based developmental pediatrician, Dr Lane Strathearn, has found a baby's smile can trigger much more than just a fuzzy feeling for a new mother.
Dr Strathearn, and his team from the Baylor College of Medicine, conducted a study which involved asking 28 first-time mothers to watch photos of their own babies, and other infants, while they were in a functional magnetic resonance imaging scanner (FMRI).
The findings of the research, which appear in the July edition of Pediatrics, revealed that when a mother sees a photograph of her own child smiling, the reward centres of her brain light up.
Dr Strathearn said the finding could help scientists explain the special mother-infant bond, and how it sometimes goes wrong.
"The relationship between mothers and infants is critical for child development," Dr Strathearn said.
"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."
A major finding was that when the mothers saw their own infants' faces, key areas of the brain associated with reward lit up during the scans.
Interestingly, the areas associated included the ventral tegmental area/substantia nigra regions, the striatum, and frontal lobe regions involved in emotion processing, cognition and motor/behavioral outputs.
"These are areas that have been activated in other experiments associated with drug addiction," Dr Strathearn said
"It may be that seeing your own baby's face is like a 'natural high'
"The strongest activation was with smiling faces.
"We were expecting a different reaction with sad faces."
In fact, the researchers noted little difference in the mothers' brains when they saw their own babies' crying face compared to that of an unknown child.
"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," Dr Strathearn said.
Dr Strathearn, who graduated from the UQ medical program in 1992, is Assistant Professor of Pediatrics at BCM and Texas Children's Hospital, and a Research Associate in BCM's Human Neuroimaging Laboratory.
Others who took part in this study included BCM's Dr P. Read Montague and Dr Jian Li, and Professor Peter Fonagy of University College London.
The research received funding from the National Institutes of Health, the Kane Family Foundation, the National Institute of Neurological Disorders and Stroke and the National Institute on Drug Abuse.
The Pediatics article, entitled "What's in a Smile? Maternal Brain Responses to Infant Facial Cues", is available here