Love hormone Oxytocin leads to maternal instincts

Washington: Scientists have unraveled how the "love hormone" oxytocin acts on brain cells to make females understand and tend to their offspring's needs.

The findings by the neuroscientists at NYU Langone Medical Center could lead to a better understanding of how oxytocin, which is better known for its role in inducing sexual attraction and orgasm, and other hormones could be used to treat behavioral problems resulting from disease or trauma to the brain.

Senior investigator of the study, Assistant Professor Robert Froemke, PhD, said that the findings redefine oxytocin as something completely different from a 'love drug,' but more as an amplifier and suppressor of neural signals in the brain. The hormone turns up the volume of social information processed in the brain.

In the study conducted on mice, Dr. Froemke and his team mapped oxytocin to unique receptor cells in the left side of the brain's cortex.

In separate experiments in adult female mice with no pups, and hence no experience with elevated oxytocin levels, adding extra oxytocin into their "virgin" brains led these mice to quickly recognize the barely audible distress calls of another mother's pups recently removed from their home nest. These adult mice quickly learned to set about fetching the pups, picking them up by the scruffs of their necks and returning them to the nest - all as if they were the pups' real mother.

This learned behavior was permanent, researchers say; the mice with no offspring continued to retrieve pups even when their oxytocin receptors were later blocked.

Lead study investigator Bianca Marlin, PhD, said that it was remarkable to watch how adding oxytocin shifted animal behavior, as mice that didn't know how to perform a social task could suddenly do it perfectly.

The findings are published online in the journal Nature.