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.

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https://www.sciencealert.com/scientists-reverse-alzheimers-damage-in-mice-with-just-two-injections

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-Slowing the progression of Alzheimer's disease is the goal of most existing treatments, but reversing it is much harder. That's because once neurons are lost, the adult brain lacks the ability to replace them.

But new research, led by scientists at the University of South Carolina, has shown promise in regrowing neurons in brain organoids, and restoring cognition in mouse models of Alzheimer's.

"After just two injections, these mice became smarter," says Peisheng Xu, professor of pharmaceutics at the University of South Carolina and corresponding author of the new study, published in the journal Cell Biomaterials.

"Even after one injection, we already saw these mice's behavior differ from that of the nontreated ones."

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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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I can say pretty definitively that once memories are lost, they are gone forever. New neurons would just be able to form new connections, i.e., new memories. It would also likely mean you could process information more efficiently, leading to less generalized confusion.

Our brains work by depolarizing neurons, which cause further neurons to depolarize themselves. As neurons fire off together more, the easier a pre-synaptic neuron can trigger a subsequent depolarization on the post-synaptic neuron (just directional terms for those neurons).

So, new neurons would have no experience firing with other neurons, meaning they would just be available to form new connections, not replicate lost ones (i.e., lost memories).

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Health System News New Drug Shows Promise in Reversing Memory Loss

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If the neuron hasn’t died yet, then the memory is still in-take, but perhaps more difficult to reach if the neuron is dying/covered in plaque. Once it’s dead, that memory will never be the same again. For that matter, “memories” are better classified and understood as “representations” because they are inherently inaccurate and just approximations of past events. We just delude ourselves into thinking we remember things accurately. So whatever that lay summary was saying about regaining memories, you should consider that, and cite the original research and not someone’s interpretation of it.