The love hormone oxytocin becomes the fear fighter in situations when a mother has to defend her child, a new study has revealed.
Researchers noticed in rats that when oxytocin levels are high, fear can raise the heart rate without provoking freezing behaviour.
The hormone is responsible for promoting social bonding behaviour between mother and child.
Oxytocin is produced in the brains of both genders but particularly in women during lactation and childbirth and intensifies the connection between the mother and child.
When someone is suddenly frightened, the person's heart rate increases and he/she tends to freeze momentarily.
"In a danger situation, you may want to maintain a fearful feeling but not be totally immobilized," Livescience quoted Ron Stoop, who researches psychiatric neuroscience at the University of Lausanne in Switzerland as saying.
Explaining it with an example, he said, when a predator attacks, a mother may need to fight to protect her offspring.
The researchers confirmed the study by injecting oxytocin directly into the brains of some rats.
They noticed that when the rats were startled by a small electric shock, their heart rates increased, but the rats that had received the extra oxytocin were far less likely to freeze.
"It's like the animals still kind of feel the fear but have the possibility to respond," Stoop added.
Researchers reveal that though there are vast differences between rodent and human biology, when it comes to fear, their brains have a lot in common with ours.
"There's really nice correlations with the effects of the amygdala in terms of anxiety in rats and mice with humans," said Jeffrey Rosen, a professor of neurobiology at the University of Delaware.
The study has been published in the journal Science.