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Headlines 13 T he onset of caregiving behaviour in mothers is largely driven by the brain, and it is not always guaranteed. Approximately 1 in 5 women will suffer from antenatal or postpartum anxiety. After birth, the brain is supercharged with hormones activating increased empathy, responsiveness and protectiveness. This hormonal response can take place for both mums and dads. Exactly how this happens is poorly understood – and it often goes wrong. For instance, the drive to protect can overstimulate the brain causing extreme anxiety instead. Contrary to popular belief, there is no specific treatment for postpartum anxiety. Current anti-depressant and anti- anxiety medications affect the entire brain’s circuitry and are not targeted to what can go wrong in the maternal brain. One reason is because we know very little about what happens in the brain postpartum. Dr Jamie McQuillan is a Research Fellow in the Centre for Neuroendocrinology at the University of Otago, Dunedin He is studying how stress and anxiety are regulated in postpartum females, to help towards developing treatments for postpartum mood disorders. Jamie is focusing on the two main regions of the brain that control maternal and paternal behaviour – the medial preoptic area (MPOA) and paraventricular nucleus (PVN). The MPOA acts as a central hub to direct our parental response, sending and receiving messages from multiple brain regions, including the PVN. The PVN mediates our response to stress, and is the brain’s secret weapon to help parents survive those first few months of sleepless nights and relentless demands. “The messages from the MPOA tell the PVN to limit its activity, reducing stress and levels of anxiety so parents can respond better to their baby,” Jamie says. “That's a very sensible thing to have in place. A stressed-out mum won’t be able to focus as well on her baby. But when that circuitry goes wrong, mum can end up with symptoms like depression, anxiety and heightened stress,” he says. “Postpartum anxiety can then lead to disengaged parenting.” Jamie is working alongside Dr Rosemary Brown, a multi award-winning scientist with 11 years’ experience in behavioural neuroendocrinology, and Dr Joon Kim, an early career researcher with a strong track record in stress neurobiology. Together they are studying the brain activity of female mice who have recently given birth. The first stage of their project is inducing anxiety in mothers using a cutting-edge technique called optogenetics, which utilises optical light to manipulate brain circuitry. Next, they will attempt to disrupt the anxiety-like behaviour and restore stress resilience and maternal behaviour using a technique called chemogenetics. This technology uses genetically-encoded molecules to target specific brain circuits and influence cell activity. “It's amazing. If you go back 10 or 15 years, we wouldn't have dreamed of doing this kind of work. We are really fortunate that we now have these tools,” Jamie says. The research team has the added advantage of an existing model of normal brain activity in a female mouse with pups, developed by a colleague. “The data from that model isn’t entirely complete, but the main finding was that the stress response in lactating mothers is very clearly reduced, which is a good starting point,” he says. The project received a $256,740, two-year grant in the Neurological Foundation’s last grant round, and is due to begin in September this year. Parents, stress, and how our brain sometimes lets us down Having a baby can be one of life’smost stressful events. Newmums can often feel pressured for a natural ‘maternal instinct’ to kick in, enabling them to care for and nurture their childwith a sense of unparalleled joy.