It’s often said that kids' minds are like a sponge. That is thanks to a thing called brain plasticity that allows the brain to “rewire” itself throughout one's life. Just like the rest of your body, the brain gets less "flexible" the older we become and we lose a lot of this plasticity. That’s why it's harder for us oldies to learn a new language or pick up a musical instrument.
Scientists at the University of Utah Health have proven it’s possible to return some of this plasticity to the brains of mice by tweaking a single gene. Eventually, the research could be used to fight against age-related cognitive decline in humans.
"It's exciting because it suggests that by just manipulating one gene in adult brains, we can boost brain plasticity," lead author Jason Shepherd, from the University of Utah Health, said in a statement. "This has implications for potentially reducing normal cognitive decline with aging, or boosting recovery from brain injury after stroke or traumatic brain injury."
Their research, published in the journal Proceedings of the National Academy of Sciences, found that a single gene called “Arc” is capable of rejuvenating plasticity in the visual cortex of middle-age mice.
The researchers explain that plasticity is like a window that can be open or shut. In a previous study, they showed that mice missing the Arc gene do not enjoy the benefits of brain plasticity and can’t adapt well to new experiences. Perhaps then, this gene played a role in keeping the window open, so to speak.
To pry deeper into this connection, the team put a “blindfold” over one eye in mice, some with Arc and some without, to deprive the visual cortex of normal input. The mice without Arc were not able to adapt to the new experience, suggesting they had a lack of brain plasticity.
The scientists then decided to up their game. They used viruses to deliver the Arc gene to middle-aged mice, which revealed that these older mice responded to visual deprivation as a youngster would.
"It was incredible to see that in adult mice, who have gone through normal development and aging, simply overexpressing Arc with a virus restored plasticity," says co-first author Kyle Jenks.
The researchers do not yet know if Arc plays a similar role in humans, nor do they understand whether plasticity in humans and mice is regulated in the same way. However, it helps challenge a fundamental idea that claims human brain plasticity cannot be reserved and suggests that Arc might be a therapeutic target for modulation in the future.