By Ruby Prosser Scully Controlling brain activity might help lengthen lifespanAmmentorp Photography / Alamy Stock Photo People who live longer have a reduced level of neural activity – involved in everything from twitching to moving your arms and thinking – compared with those who have shorter lives. A protein known to protect the ageing brain from dementia appears to be responsible for the difference, a discovery that might pave the way for drugs to increase lifespan. Bruce Yankner at Harvard University and his colleagues wanted to understand how gene expression in the brain – the way genes are turned on or off – affects lifespan in humans. They studied brain tissue from hundreds of cognitively healthy humans who had died between the ages of 60 and 100. When they compared the samples from those who died before the age of 80 with those who were at least 85 when they died, the team found that those who lived the longest had fewer genes related to neural excitation switched on. Advertisement To find out if this might be a factor in lifespan, Yankner and his colleagues then used drugs to suppress neural excitation in nematode worms. The more they suppressed neural excitation, the longer the worms lived on average. Worms genetically engineered to have a gene that suppresses neural activity also lived longer. The relationship went both ways, says Yankner. “Reducing excitatory activity in the worm increases lifespan, whereas increasing excitation reduces it.” Read more: Only one in five UK adults would choose to live forever if they could The level of neural activity in mammals is regulated by a protein known as REST. Mice bred without this gene had much higher rates of neural activity in the brain compared with normal mice. “This protein suppresses neural genes in humans, mice and worms,” says Yankner. “Mice that lack the REST gene in the brain show elevated neural activity as they age.” The protein has previously been shown to protect the brain from dementia and other disorders. In this study, Yankner and his colleagues found that that levels of REST in the nuclei of brain cells of people who lived to age 100 were significantly higher than those who died younger. “Initially it seemed counter-intuitive that suppressing neural activity would extend lifespan without deleterious side effects,” he says. The researchers suspect the benefit comes from suppressing excessive activity that might prove harmful. Even so, it was surprising that something as short-lived as neural circuit activity could have such far-ranging impacts on someone’s lifespan, says Yankner. He is optimistic that therapies designed to reduce excessive neural circuit activity could work. The findings raise the possibility that activities such as meditation could also work on these pathways to boost longevity. Journal reference: Nature, DOI: 10.1038/s41586-019-1647-8 More on these topics: neuroscience age
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