5 years ago, Tal Iram, a neuroscientist at the University of Stanford, came up with a surprising proposal: She approached her supervisor to talk about it. Her idea was to reverse memory loss in older mice. For that, she wanted to extract fluid from the brain cavities of young mice.

She planned to inject the brain fluid into the brains of older mice. She was confident that she could reverse memory loss in older mice this way.

And do you know what happened then?

It worked!


“When we discussed this initially, I said, ‘This is so difficult that I’m not sure this is going to work,’” said co-author Tony Wyss-Coray, professor at Stanford University in California.


In this groundbreaking new experiment, scientists successfully reversed memory loss in older mice by injecting them with a brain liquid called cerebrospinal fluid from younger mice. To help clear out waste, the cerebrospinal fluid (CSF) washes in and out of grey and white matter in waves.

This liquid can lave the tissue with proteins, or growth factors, that are important for normal and healthy development. The amount of cerebrospinal fluid reduces in our brains as we get older. And this reduction will increase the risk of Alzheimer’s and other brain or neurological conditions. The cerebrospinal fluid taken from the young mice was infused into the brains of 18-month-old animals using a tiny tube and pump. 18 months in animals is equivalent to about 60 in human years. Scientists then scanned the brain activity of older mice.


The scan result showed the experiment surprisingly boosted myelin production, myelin is a fatty substance that protects neurons from damage. It wraps around nerve fibers and serves to increase the speed of electrical communication between neurons.

“It highlights this notion that cerebrospinal fluid could be used as a medium to manipulate the brain,” Dr. Iram said.


mice brain

After a few weeks, the mice were exposed to a tone and a flashing light. Scientists found that the elderly mice got better at a ‘fear-conditioning task’. They remembered the tone and flashing light meant they were about to receive a small electric shock.


“Brain aging underlies dementia and neurodegenerative diseases, imposing an immense societal burden,” said Tony Wyss-Coray, “Memory improvements that are seen in old mice receiving CSF from younger animals may be attributed to growth factors that are shown to restore neural cell function.”

“The findings demonstrate the potential rejuvenating properties of young CSF for the aging brain,” he added.




A technique called RNA sequencing showed the therapy altered gene expression in the hippocampus that controls memory. It stimulated a type of cells called Oligodendrocytes in the central nervous system. These cells make myelin and ensure strong signals between neurons.


“As the brain ages, cognitive decline increases along with the risk of dementia and neurodegenerative disease,” Prof. Wyss-Coray explained. “An understanding of how systemic factors affect the brain throughout life has shed light on potential treatments to slow brain aging.”

“The CSF is part of the immediate environment of the brain, providing brain cells with nutrients, signaling molecules, and growth factors,” he added.


Age-related cognitive decline is common in people aged over 60. But we can prevent it by keeping a healthy diet and regular exercise. But there are no pharmacological treatments.

“I like doing these types of studies that require a lot of perseverance,” Dr. Iram said. “I just set on a goal, and I don’t stop.”

Now, this experiment opened the magical door to new brain treatments. According to scientists, we could reverse memory loss and delay cognitive decline.


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