Mother's behaviour can greatly influence child's oxytocin system: Study

A new study suggests that mothers' behaviour can have a substantial impact on their children who are in the process of developing oxytocin systems.

Oxytocin is an extremely important hormone, involved in social interaction and bonding in mammals, including humans. It helps us relate to others. It strengthens trust, closeness in relationships, and can be triggered by eye contact, empathy, or pleasant touch. It's well known that a new mother's oxytocin levels can influence her behaviour and as a result, the bond she makes with her baby.

A new epigenetic study by Kathleen Krol and Jessica Connelly from the University of Virginia and Tobias Grossmann from the Max Planck Institute for Human Cognitive and Brain Sciences now suggested that mothers' behaviour affects their children's developing oxytocin systems.

Childhood marks a dynamic and malleable phase of postnatal development. Many bodily systems are coming online, maturing, or getting tweaked, often setting our psychological and behavioural trajectories well into adulthood.

Nature plays an obvious role, shaping us through our genes. But we are also heavily influenced by our interactions, with other people, and with our environment.

The scientists observed a free play interaction between mothers and their five-month-old children, reported the study published in the journal 'Science Advances'.

"We collected saliva samples from both the mother and the infant during the visit and then a year later, when the child was 18 months old," said Kathleen Krol, a Hartwell postdoctoral fellow in Connelly's Lab at the University of Virginia who conducted the study together with Tobias Grossmann at MPI CBS in Leipzig.

"We were interested in exploring whether the involvement of the mother, in the original play session, would have an influence on the oxytocin receptor gene of the child, a year later," continued Kathleen Krol.

"The oxytocin receptor is essential for the hormone oxytocin to exert its effects and the gene can determine how many are produced," explained Kathleen Krol.

"We found that epigenetic changes had occurred in the infant's DNA and that this change was predicted by the quality of the mother's involvement in the play session. If mothers were particularly involved in the game with their children, there was a greater reduction in DNA methylation of the oxytocin receptor gene one year later," said the scientist.

"Decreased DNA methylation in this region has previously been associated with increased expression of the oxytocin receptor gene. Thus, greater maternal involvement seems to have the potential to unregulated the oxytocin system in human offspring," explained the scientist.

"Importantly, we also found that the DNA methylation levels reflected infant temperament, which was reported to us by the parents. The children with higher methylation levels at 18-months, and presumably lower levels of oxytocin receptor were also more temperamental and less well balanced," continued the scientists.