Dopamine is responsible for maternal bonding, says study

A new study used state-of-the-art technology to determine that dopamine is responsible for maternal bonding.

The authors of the study, entitled “Dopamine in the medial amygdala network mediates human bonding” which was published recently in the journal Proceedings of the National Academy of Sciences, say this is the first attempt to examine the neurochemistry of human social affiliation. They say neural mecahnisms have been studied in rodents that point to the same conclusion, but by using new technology in the form of a an fMRI and a PET scanner that probed mothers’ dopamine responses to their infants, they were able to examine the dopamine function. The fMRI, or functional magnetic resonance imaging and PET positron emission tomography scanner, performed a pair of brain scans at the same time.

In the human brain, the organic chemical dopamine functions as a neurotransmitter; a chemical released by nerve cells that sends signals to other nerve cells.

“The infant brain is very different from the mature adult brain—it is not fully formed,” says Northeastern psychology professor Lisa Feldman Barrett, one of the study’s authors. “Infants are completely dependent on their caregivers. Whether they get enough to eat, the right kind of nutrients, whether they’re kept warm or cool enough, whether they’re hugged enough and get enough social attention, all these things are important to normal brain development. Our study shows clearly that a biological process in one person’s brain, the mother’s, is linked to behavior that gives the child the social input that will help wire his or her brain normally. That means parents’ ability to keep their infants cared for leads to optimal brain development, which over the years results in better adult health and greater productivity.”

The study looked at 19 mothers between the ages of 21 to 42 years-old who had no psychiatric history and were not breastfeeding or pregnant. The researchers visited the homes of the particpants and videotaped them watching films of their own infant and an unfamiliar infant and collected PET data for an hour-and-a-half. The data the researchers gathered, they say, suggest that mother and child being on the same frequency is associated with increased dopamine responses within the network and decreased plasma oxytocin.

Barrett says the oft-repeated idea that strong social ties are essential to a happy life is underscored by this study.

“We found that social affiliation is a potent stimulator of dopamine,” says Barrett. “This link implies that strong social relationships have the potential to improve your outcome if you have a disease, such as depression, where dopamine is compromised. We already know that people deal with illness better when they have a strong social network. What our study suggests is that caring for others, not just receiving caring, may have the ability to increase your dopamine levels.”

Barrett says the study has implications for the way society looks at early child development.

“(The findings of the study) have the potential to reveal how the social environment impacts the developing brain,” she says. “People’s future health, mental and physical, is affected by the kind of care they receive when they are babies. If we want to invest wisely in the health of our country, we should concentrate on infants and children, eradicating the adverse conditions that interfere with brain development.”

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