Tiny grins light up reward centers that lead to quality care, study says. Any mother who’s ever felt a jolt of joy at her baby’s first grin knows how intoxicating that can be.
Now, scientists at the Baylor College of Medicine say there’s more to the baby buzz than just a rush of happy feelings. Turns out that seeing your own child smile actually activates the pleasure receptors in the brain typically associated with food, sex — and drug addiction.
“It may be that seeing your own baby’s face is like a ‘natural high,’ said Lane Strathearn, an assistant professor of pediatrics at Baylor and and Texas Children’s Hospital who studied the brain reactions of 28 first-time moms.
“We know similar brain circuits are activated,” he added. “Whether that feels the same as a shot of cocaine, I’m not sure.”
Strathearn and his team used functional magnetic resonance imaging to scan the mothers’ brain reactions to photographs of their own 5-month to 10-month-old babies and those of others in three emotional states: happy, neutral and sad.
As expected, the sight of their own happy babies sent blood rushing to the moms’ brain regions associated with dopamine, a neurotransmitter that plays an important role in addiction. The spike rewarded the mothers with a neural kick that prompted them to want to take action to care for their babies, Strathearn said.
“It makes sense biologically,” said Strathearn, whose work is published in the latest issue of the journal Pediatrics. “It establishes that bond between parent and child.”
The work is important, Strathearn said, not only because it documents the brain activity of healthy moms, but also because it could provide a baseline for studying the brains of abusive or addicted mothers and lead to possible interventions.
“We want to understand what happens in this relationship with mothers and babies,” added Strathearn, who is a research associate in Baylor’s Human Neuroimaging Laboratory.
No spike for crying babies
Surprisingly, however, the moms in the study didn’t respond as strongly to their own infants when their expressions were neutral — or when they were in distress. The neural scans showed the mothers responded to all crying infants about the same, by activating areas of the brain involved in conflict.
“We were expecting a different reaction with sad faces,” Strathearn said. Although it’s not exactly clear, that could mean that mothers are wired to react to all crying babies, not just their own.
The new study provides important insights into maternal responses to babies’ emotional cues, said Regina Sullivan, a researcher at Joe LeDoux’s Emotional Brain Institute, which is affiliated with the National S. Kline Institute for Psychiatric Research and New York University.
But it doesn’t clear up one big mystery of brain study: Are the documented brain reactions the result of instinct or socialization?
“We don’t know whether this response is learned or innate,” Sullivan said. “People tend to think that we’re innately good parents, but it so happens that parenting in humans and in non-human primates has to be learned.”
‘It’s got to be like crack’
Whether she responded because of instinct or expectation, the results of the study were no surprise to Katrina Lyons, 39, a Houston high school science teacher who joined the research project three years ago, just before the birth of her first son.
Lyons said it’s hard even to describe the joy she felt at the sight of Aiden’s first smiles or those of his brother, Jack, who is 1.
“Does it feel like a high? Oh, yeah,” said Lyons, who surrounds herself with photos of her boys. “It’s got to be like crack. I just have to see them everywhere.”
The Pediatrics study focused on the brain reactions of well-educated, middle-class mothers, but it could have implications for others. Moms who are depressed, for instance, typically fail to respond to their smiling babies.
And other studies have shown that using cocaine, a drug that activates the dopamine reward systems, might interfere with the brain perks prompted by smiling babies. That could explain high rates of child abuse among cocaine-addicted mothers, Strathearn said.
Other scientists are looking at the effects of infant emotions on fathers, but the current study was limited to biological mothers and babies, Strathern noted.
His work was funded by the National Institutes of Health, the Kane Family Foundation, the National Institute of Neurological Disorders and Stroke and the National Institute on Drug Abuse.
If the research can help, Lyons said she was happy to participate.
“I think that’s good for all babies,” she said. “Everybody deserves a mama who loves them.”
By JoNel Aleccia
© 2008 MSNBC Interactive
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