Increased brain function could stimulate a chemical that protects nerve fibres from multiple sclerosis (MS), a study suggests.
Researchers at Edinburgh University treated zebrafish with drugs that produced a similar reaction to touch or proximity to a predator, leading to increased brain function and production of a protective coating called myelin.
It is too early to say whether increased brain function leads to more myelin production in humans, according to researchers.
Other studies have shown that activities such as learning piano, juggling or doing puzzles stimulates brain growth, Edinburgh University researcher Dr Sigrid Mensch said.
"At the moment we are just looking at brain activity, which is a very complex system, so we couldn't predict that doing crosswords would eventually lead to more myelin," she said.
"But there are other studies that show something like learning the piano or juggling have increased white matter, which is essentially myelinated axons.
"The drugs increased the escape response in the zebrafish, which is triggered by the sight of a predator or a touch that leads to increased movement.
"We then saw increased myelin generation, but it's very complex so it might not be translatable to humans."
Myelin protects nerve fibres, known as axons, and speeds up the transfer of information.