Mice learn how to mother through observation, and experienced mouse mothers tutor inexperienced female mice in the practice of mothering before they have babies of their own, according to a new study in the journal Nature.
The research, from New York University (NYU), also reveals that the oft-described ‘love hormone’, oxytocin, plays a critical role in this learning process.
The study involved round-the-clock filming of female mice interacting in a community of mothers, newborns and virgin females. Building on previous research that showed the core importance of oxytocin to maternal behaviours in mice, the researchers took electrical readings in several brain regions known to produce oxytocin.
The team found that new mouse mothers would shepherd virgin female mice into the nest along with their pups, triggering the virgin mice to mimic this shepherding behaviour with the pups. The same effect was found when the virgin mice simply watched this behaviour through a clear plastic window.
Interestingly, the team found that both the sight and sound of crying pups moved outside of the nest stimulated oxytocin production in a particular brain region: when this brain region was chemically blocked, virgin mice did not learn how to take care of the pups.
“Our study shows that in mice the best way to be a mum is to watch and learn from an experienced mum,” says study senior investigator Robert Froemke, a professor in the Skirball Institute of Biomolecular Medicine at NYU Langone Health. “Given the evidence, we propose that similar mechanisms operate in human mothers.”
Oxytocin is known for its core role in female reproduction: it’s released in large amounts during labour, and facilitates childbirth and breastfeeding. There’s also evidence of its central involvement in the process of bonding, socialisation and sexual enjoyment in humans. Writing in National Geographic in 2015, science journalist Ed Yong described the hormone as “an all-purpose social molecule” that draws our attention to social cues.
This new research builds on our growing knowledge about this fascinating social facilitator, and shows that learning mothering skills through observation among mice (and potentially, among humans) is not just a practical process, but guided by the bonding hormone.
“This work redefines oxytocin’s role in brain function, broadening its impact to include formidable and complex social networking activities that force the brain to pay attention and adapt to its surroundings at the time, whether it’s reacting to the sound of a pup’s cries or feelings of happiness,” says Froemke.
Next, the team will investigate whether the same tutoring relationship exists among mouse fathers and virgin males.