Newborn mice shriek frantically when mom’s away unless they have a defect in the same brain pathway that responds to morphine, says research that sheds new light on mother-infant bonding.

Beyond unraveling the biology of that most basic of bonds, the work also may offer new leads to better understand autism, a disorder characterized by poor social attachment, scientists from Italy’s National Research Center report.

At issue is the brain’s opioid system, best known for its role in pain, pleasure and addiction. Opioid drugs like morphine act on that system to block physical pain.

But there have long been clues that the pathway plays a role in some basic emotional pain, too, because giving morphine to animals can decrease their social behaviors.

Thus, one theory behind autism’s symptom of social indifference is that the brain might be incapable of forming strong social bonds without feedback from its opioid reward system like the pleasure a baby should feel from loving parental care.

More here.