How would being de-aged affect the brain?

Speculative question for Fridge Logic purposes.

We've all seen the Fountain of Youth trope. But, one thing has always made me wonder: how does being aged down affect the brain? I believe it's scientifically factual that the human brain behaves differently as you age (for example, infants can't form conscious memories, and children learn at a faster pace than adults). However, how does your memory stand up? Do you forget things as you get younger? Will being turned back into a baby/fetus/embryo/zygote erase your memory? If you age up again, will you have any memory of your "former" life?

Hm.. when adults get de-aged back to children/babies, would you like for them to retain their memories, and what they've learned? That would have them behave differently still if they're younger; parts of behaviour get changed because they haven't gone through puberty, and young children do have eidetic memory which fades when they grow older. (They have vivid imaginations, those young tykes.)

As well, they'll have some trouble making wide-scale comprehension; things like settling in tax rebates and driving they would likely find difficult, even if they do remember doing these things beforehand. A little lax on the impulse control— if you de-age them to being toddler or younger, I think the adult memories retained wouldn't hold much for them - these memories have complicated emotions and meanings (like infatuation, cool calculation) which eludes their grasp.

If you put them to zygote state - the faculties of brain are not yet fully formed; so the memories might get lost down the track. And if you re-age them up again — I think some remnants of them will get more easily formed, as how a river treads the path which has been worn down before; they'll have bad distorted, reconstructed remembrances.

I still wanna be a young kid again - it was fun growing up.. *sighs*

edited 3rd Aug '11 11:41:19 AM by QQQQQ

If you could establish the parameters for the process, you'd want people to retain their memories, wouldn't you? So the brain would be off limits, and you'd change the body around it.

Mental abilities come from chemical patterns stored in groups of neurons. If you rearrange those neurons, then you alter the mind. In effect you cause brain damage. The subject may lose certain memories or skills. In extreme cases s/he may have to learn how to eat, speak, walk, and solve problems ... which is what happens in infancy anyway.

One little problem there. If you didn't alter the brain, you'd basically have an old brain (I.E. one more likely to fail due to accumulated mutations and such other results of aging), so, it would render the whole point of de-aging the body kind of moot.

I was curious about the circumstance in general, but here's the specific scenario I'm constructing as a Freudian Excuse for my Big Bad.

He's a genetic combination of my story's three races. The Cosmic Being that created him tried making Gattaca Babies with all three genetic traits before, but none of them turned out the way she wished (she wants an avatar which will allow her to retain full control over her power. To her surprise, though, thanks to some Bizarre Alien Biology, a Brainy Baby is conceived with three biological parents from each of the races. She gleefully takes the child and experiments on him in an environment which bends time to her will.

As a decade passes in the world outside, the Big Bad is put through horrific life after horrific life—every waking moment, he's tested, tormented, and put through trial after trial as she tests the limits of his capabilities. The first time, he only lives up to 05% of the potential she knows he has, so she de-ages him and tries again. The next time, he goes up to 06%...and so on, and so on. By the time she's finished, he's lived dozens of lifetimes and has peaked at 15% of his potential, and she's very frustrated. (Keep in mind that 15% of his potential is still enough for a Super Power Lottery by mundane standards.)

Later on, she find out what she's doing wrong, but by that point, she's pretty much driven him insane.

edited 3rd Aug '11 12:09:05 PM by KingZeal

The development of a human's brain is directly linked to that human's physical development as a child and an adolescent (which is, in turn, influenced positively by good physiological and psychological health. People who receive absolutely no loving contact from a parental figure do not develop psychologically, if they live to see adulthood.)

Remember that you cannot fit the brain of an adult into the skull of the baby. The baby may have more neuron tissue densely packed into one small head, but this tissue has much less connections (save for those that manage the heart and other automatic processes) because these are supposed to develop after birth through learning. A baby learns faster and much more than an adult, but the connections are also very quickly pruned of those never used.

Here's a good concept to think about: What happens when you compress the revitalized mind of an adult into a brain which is influenced to learn quickly and indiscriminately, and to prune unused information?

Now, what if you compressed the same adult mind into the brain of a child? Or a preteen? An adolescent? You have a lot of psychological and neurological research ahead of you.

And that's not even approaching the concept of "de-aging" itself. Suppose you had all the medicinal faculties to repair the damage done to cells over time for a variety of reasons (though you can't bring back to life cells that are already dead and gone, that's silly). How do you discriminate damage from damage?

For one example of a tissue that experiences damage all the time as a part of its function, consider red blood cells. Mature red blood cells are almost metabolically dead—they have dissolved their nuclei, and all their organelles save for the occasional mitochondrion. This is to use up as much cytoplasmic volume for hemoglobin as possible and maximize oxygen-carrying capacity. Predictably, because they cannot repair themselves (you need a nucleus and ribosomes to do that), they sustain additional damage and die all the time, so the spleen, liver and a few other organs are charged with the duty of examining the blood and destroying all damaged blood cells.

(Cells with no nuclei and ribosomes are probably already too damaged to be healed because they cannot repair themselves, but immature blood cells still have their ribosomes and nuclei. These have to be the last to go so that hemoglobin can be produced.)

Another example is the epidermis, that is, the skin. The epidermis is composed of many layers of squamous cells, but only the base layer is as healthy and living as other internal skin tissue. The base layer is constantly dividing and producing new cells, which are pushed up higher into the epidermis. These cells develop more and more keratin (a protein that hardens and toughens the cell—your nails and hair are made mostly of keratin), but keratinization chokes the cell's functions and kills it, so that by the time it reaches the top layer of your skin it is dead. Dead skin cells are always flaking off, so the base layer has to continue producing new cells.

(Aren't you glad you're not an individual body cell?)

All of this damage is necessary for the body to function at the best of its ability, but how do you tell your medicine to discriminate the damage caused by aging from the damage caused by normal bodily functions?

Have you heard of telomeres? They're new to me too.

They're essentially caps of junk DNA on the ends of each chromosome whose purpose is to protect the ends of the chromosomes (that is, the part that actually codes for proteins) themselves from damaging in replication—so the telomeres get damaged instead, and get continually more and more damage with each cell division. Apparently once the telomeres are done, the cell can no longer divide. Apparently telomere damage is the cause of senescence. If a cell cannot divide, it can only age.

There is a solution however, and that is telomerase reverse transcriptase, the enzyme that can rebuild telomeres. It's believed that turning this enzyme back on can help delay senescence, but we don't know much about this yet and I know even less.

I highly doubt rebuilding telomeres can turn someone back into a kid, though. If you're going to apply other medicinal faculties that can turn somebody back into a kid, however, you're going to need to rebuild telomeres to keep the kid from getting wrinkles.

Bone lengthening! Bone lengthening! How are you going to reverse bone lengthening?

We all have heard of bones growing longer, but bone tissue only breaks down at the center, creating the cavity and never on the sides! Thus, I don't think bones are able to grow shorter.

edited 3rd Aug '11 12:56:22 PM by annebeeche

My thinking was that, since the body replaces each cell over a span of seven years, the brain would be revitalized as part of a young body, while keeping the old patterns (memories, that is) intact. You'd have an adjustment period while your young hormones kept your old brain juiced up. There's an example of the process in Holy Fire by Bruce Sterling.

Actually no, not each cell. That's why we have permanent tissue damage.

I don't think neurons get replaced often, for example.

I know for a fact ova don't.

You might want to look into Alzheimer's disease for some insights. When you have the disease, memory seems to start erasing backward, beginning with the most recent memories and the ability to create new memories. Memory loss aside, the progression of the disease resembles aging backwards rapidly, eventually landing you back in an infantile state.

Something interesting (to me anyway) is that as you lose your memories of people, your facial recognition usually remains intact because that information is stored separately in the brain. So while you may recognize your children as people you know, you won't be able to remember who they are or how you know them.