It has long been known that mothers’ brains get rewired after giving birth, which increases their devotion to their newborns. But now, University of Otago researchers have discovered how that happens, and hope their findings may feed into future research and development of treatments for mood disorders which are specifically tailored for pregnancy and for use during breastfeeding. Co-lead author and Otago physiology researcher Dr Michael Perkinson said a hormone has been found responsible for making mothers’ interactions with their newborns feel rewarding, rather than just necessary. New research showed an essential pathway in the brain switched on when a mother was interacting with her baby, enabling her to devote more energy to providing for its needs. Dr Perkinson said the discovery was found using mice. The mouse’s brain was switched on when prolactin — a hormone essential for milk production — reacted with a hormone-sensing part of the brain, and dopamine was released to the brain’s reward centre. “When we artificially activated this part of the brain, mice that had never had pups suddenly acted like devoted new mothers. “When we blocked it in mothers, their normal surge of interest in pups didn’t happen. “We know the brain’s reward system gets rewired after birth to prioritise offspring. “Our findings help explain how that rewiring might happen, showing that prolactin, acting through this specific pathway, tips the balance and makes time with a newborn feel rewarding rather than just necessary.” Senior author and fellow physiology researcher Associate Prof Rosie Brown said the research was helpful for mothers to understand why the way they thought and felt changed so profoundly during pregnancy, and after the birth of their child. “The brain is undergoing remarkable change during pregnancy that really shapes the way we think and feel. “It’s not surprising that sometimes these changes can be difficult. “Mothers and families need support and tools to positively shape this critical period of life.” It was hoped the findings would feed into future research and development of treatments for mood disorders, she said. “Around one in five new mothers in Aotearoa New Zealand suffer from peripartum mood disorders. “However, there are very little treatment options available for pregnant or postpartum mums that specifically target the cause of mood disruption during this time. “We are trying to understand how the brain is critically changing during pregnancy to bring about healthy changes in mood in mothers that enable them to thrive during this stage of life. “By understanding how mood and behaviour are regulated in mothers, we can target the cause of disrupted mood, and effectively peripartum mood disorders.” Dr Perkinson also hoped the research would help take some stigma away from parents who struggled to bond with their baby. “It points to a brain pathway that isn’t switching on as expected, not a personal failing,” she said. john.lewis@odt.co.nz
