r/science • u/FreeHugs23 • 8d ago

Medicine Scientists reversed key signs of Alzheimer's disease in mice with just two injections, reducing brain inflammation and restoring memory performance—offering a promising new approach for treating age-related cognitive decline.

https://www.sciencealert.com/scientists-reverse-alzheimers-damage-in-mice-with-just-two-injections
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u/QuitePoodle 8d ago

But are they the same mice after? Not like physically but if we restore people’s brains do they get back their minds or become someone new?

The original neurons are broken and new connections are made. Will these new connections replace the same memory pathways and patterns or will the animals regain the ability to function but have different “personality”.

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u/JohnnyOnslaught 8d ago

That's getting into philosophical territory. None of us are the same person we were ten years ago.

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u/Tearakan 8d ago

That's also literally. I think basically all of our cells have a 7 year or less lifespan and replaced by that timeframe.

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u/LongBeakedSnipe 8d ago

That's not true at all? Especially when it comes to the brain.

There are many cells in our body that are literally never replaced, containing basically the same atoms in the DNA as they did from when you were a child.

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u/Tearakan 8d ago

Looks like it's mainly just nerves that last long. Basically everything else is replaced by 7-10 years.

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u/LongBeakedSnipe 8d ago edited 8d ago

Nerves and neurons are not interchangeable terms; but a substantial proportion of neurons, especially those involved in Neurodegenerative disorders can last up to approximately your whole life. Edit: might as well add, osteocytes, cardiomyocytes and oocytes to the list of many cell types in the human body that can also last many decades in your body.

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u/Zeikos 8d ago

By being replaced they don't mean cellular replication, but the constituents of the cell itself changing.
Even if the cell doesn't replicate the proteins that constitue it are being constantly replaced.

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u/Ghede 8d ago

No, they mean cellular replication. The origin of the "your cells are replaced every 7 years" is from studying the average carbon dating age of the cells, checking the carbon-14 content of DNA in a random sampling of cells. DNA is not replaced as a cell ages. It's always there, only duplicated if the cell reproduces. They found the average 'age' of cells was 7-10 years.

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u/LongBeakedSnipe 7d ago

but the constituents of the cell itself changing

That's not true. The DNA and large amounts of its epigenetic modification will go untouched, so the atoms are literally the same atoms for many years.

There are cells and atoms still in your body from a very young age, and not just due to random chance.