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The 'love hormone', oxytocin, has long been known to promote bonding between a mother and a child.

Now scientists have shown it does this by permanently change the nerve pathways in the brain that control certain social behaviours.

Researchers believe the results could lead to new ways of using the hormone to treat psychological problems such as stress and speech disorders.

The 'love hormone', oxytocin, has long been known to promote bonding between a mother and child. Now scientists have shown it does this by change the nerve pathways in the brain that control social behaviours

'Our findings redefine oxytocin as something completely different from a 'love drug,' but more as an amplifier and suppressor of neural signals in the brain,' said Robert Froemke, PhD, an assistant professor at NYU Langone.

'We found that oxytocin turns up the volume of social information processed in the brain.

'This suggests that it could one day be used to treat social anxiety, post-traumatic stress disorder, speech and language disorders, and even psychological issues stemming from child abuse.'

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

They found that the hormone controls the volume of 'social information' processed by individual neurons, curbing so-called excitatory or inhibitory signals.

It is also responsible for rapidly determining how female mice with pups responded to cries for help and attention.

In separate experiments in adult female mice with no pups, adding extra oxytocin into their 'virgin' brains led these mice to quickly recognise the barely audible distress calls of another mother's pups.

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.

By adding oxytocin into their 'virgin' brains of mice, they were able to more easily recognise and respond to the cries of baby mice. Pictured are success retrieval rates over time. Each point on the graph is the average of 10 two minute trials after injective of the different substances

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

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

Researchers at NYU Langone created an antibody that specifically binds to oxytocin-receptor proteins on each neuron, allowing the cells to be seen with a microscope.

'Our future research includes further experiments to understand the natural conditions, beyond childbirth, under which oxytocin is released in the brain,' Dr Froemke said.

Researchers believe the results could lead to new ways of using the hormone to treat psychological problems such as stress and speech disorders