The claim that women’s brains are four years younger than men’s may at first cause confusion. Since a young age, women have been so often reminded that our brains develop quicker than our male counterparts – which is entirely true. In fact, in 2013, scientists from Newcastle University confirmed that women optimise brain connections much earlier than boys during development, thus leading to the obvious differences in maturity during adolescence. There’s no cause for alarm as that paper has yet to be proven wrong, but instead, novel research has revealed yet another difference in the brains of males and females.
Released just last week, this new paper has focused on the brain’s metabolism and uncovered interesting findings concerning differences between the sexes.
To begin to explain this, it’s easiest to describe what is meant by ‘brain metabolism.’ Our brains need a lot of energy. Even when we’re resting, the brain makes up approximately a quarter of our energy requirements and it gets this energy from glucose. The brain, as the control centre of our bodies, requires a constant supply of glucose and so it must be constantly metabolising in order to keep everything working as it should be. As you can imagine, like any organ, after consistently performing the same task for years on end, over time the brain’s metabolism slows down. Scientists have known for a while now that how the brain metabolises energy changes over a lifespan and even that there are considerable sex differences within in the process, however up until now this had never been studied in vivo.
Yet, as published recently in Proceedings of the National Academy of Sciences, these sex differences have now been confirmed. The team of researchers, led by Manu Goyal of Washington University in St Louis, underwent PET scans which measured the flow of oxygen and glucose in their brains. Following this, they created an algorithm to find a relationship between chronological age and brain metabolism by feeding it the data from all the participants involved. After this, the researchers flipped the algorithm so that they would feed it a woman’s metabolism data and require it to output an age. They found that the algorithm would consistently provide an age on average 3.8 years younger than the actual ages of the women. Oppositely, when then given the metabolism for a man and asked to yield his true age, the algorithm would give an age approximately 2.4 years older. These findings even held in even the youngest participants in the study, who were only in their twenties.
As explained by the lead researcher: “it’s not that men’s brains age faster – they start adulthood about three years older than women, and that persists throughout life,” said Goyal. “What we don’t know is what it means. I think this could mean that the reason women don’t experience as much cognitive decline in later years is because their brains are effectively younger, and we’re currently working on a study to confirm that.”
If future research could be directed into the effects of this finding it could lead to great advancements into the research and treatment of neurodegenerative diseases such as Alzheimer’s. Alternatively, if techniques such as this could accurately reveal someone’s brain age then it may be possible to better predict who is less or more likely to struggle with cognitive issues as they get older. As a follow-up study, Goyal, Raichle, Vlassenko and colleagues are now studying a cohort of adults over time to see whether people with younger-looking brains are less likely to develop cognitive problems.
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