​New York, Feb 19 (IANS) In a first, researchers have found that neurotransmitter dopamine -- a chemical that acts in various brain systems to spark the motivation necessary to work for a reward -- was involved in human bonding.

In the research, published in the journal Proceedings of the National Academy of Sciences, a researcher studied 19 mother-infant pairs and found that the results had important implications for therapies addressing disorders of the dopamine system.

"The infant brain is very different from the mature adult brain -- it is not fully formed," said Lisa Feldman Barrett of Northeastern University psychology.

"Our study shows that a biological process in one person's brain, the mother's, is linked to behaviour 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," Barrett added.

To conduct the study, the researchers used a machine capable of performing two types of brain scans simultaneously--functional magnetic resonance imaging, or fMRI and positron emission tomography, or PET.

fMRI studied the brain in slices, front to back, like a loaf of bread and tracked blood flow to its various parts. 

Barrett's team tied the mothers' level of dopamine to her degree of synchrony with her infant as well as to the strength of the connection within a brain network called the medial amygdala network that, within the social realm, supports social affiliation.

"We found that social affiliation is a potent stimulator of dopamine. 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," Barrett noted.