Increasing Speed of Neural Transmission by Embedding Material in Myelin Sheaths

Question

I am building a science fiction world 100+ in the future with various human augmetics. One of the things I would like to do is speed up human thought. My preferred mechanism for embedding this material is nanites.

From what I gather Increased myelinization increases signal speed within a neuron. The way I propose to accomplish this is to embed additional insulative material into existing myelin sheaths.

Is this possible? Is there, even speculatively, a material that would allow me to do this? Is there another mechanism that would allow nanites to modify existing neurons so that they fire faster?

Answer 1

I think there might be another way. Increased myelinization is not going to help much, since signal propagation delays are an integral part of the extant network and the way it works. Increasing transmission speed might just get you a migraine or a case of the petit mal.

But we're now, in 2020, experimenting with neural plasticity. What this means is - most brain cells are not born for a specific purpose; rather they are recruited by the various neural structures, and undergo pruning. This is how someone might recover from brain damage: different structures are re-recruited and re-purposed to take the role of nonfunctional ones.

One of the several ways this could be used is in curing dementia, brain damage and Alzheimer's Disease.

But what would happen if we were to supply fresh, recruitable cells - or cell analogs - to a working, healthy brain? If the brain had need of that extra power, it would recruit those cells just like it did through infancy and adolescence. Except that now these cells' performances do not need to match those of a real neuron; the existing brain will just leverage and integrate whatever response patterns the new cells show, without "knowing" or "expecting" them to perform in any particular way. In time, this provides more raw "brain power", and may supply extra features.

New artificial cells - your "nanites" - can first help, then learn from, and finally duplicate and replace the old cells, one at a time. Once a sufficient volume of the brain is running on artificial hardware, closely emulating a real human neural network, nothing stops you from speeding up the clock.

There are other possibilities too: for example, the cell replacement can go on forever, providing what is in effect immortality. Also, when the whole brain is actually a large bioengineered artificial network, you can send a signal and have each neuron instantly "freeze" its state, while autonomic functions get emulated elsewhere. Each neuron can now be individually contacted and its state read, taking a "snapshot" of the whole large network. Then the brain is un-paused, but a backup has been created with the information required to reassemble an identical network and prime it with the same data.

Also, with the information supplied by the first "neuristor" cells, it would be soon possible to create artificial memories. An artificial short-term memory is working knowledge: imagine looking at someone and immediately remembering all useful available information on them, from the name to the last known occupation or any notes you might have made. Fast integration of knowledge on this scale would provide something very similar to genius-level intelligence, if not yet intuition.

Answer 2

You could try to synthetically copy the mechanism that builds the insulation in the development during pregnancy.

Here the enzyme FASN (fatty acid synthase) is critical to built from fatty acids of different kind and in the right amount each, the lipid rich membrane structure called myelin, that enwrappes the axons. (source )

So your nanites need the right amount of every lipid, and the FASN as tool to built up more of the myelin. No special insulating ingredients are needed, because you built up onto an development, that showed it's effectiveness for millions of years.

If you insist on a new material, then use some new advanced lipid (fatty acid), that would be the saves way, to fit into the system and not causing side effects.

Answer 3

Better insulation does not mean greater speed.

Your idea of improving insulation would not have any actual benefit because neuron, as they are, are well enough insulated by myelin. In reality what myelin does is separate parts of the neuron that can be excited (i.e. activated by the electrical signals) from parts that can not be excited.

Imagine dominos. If you have small, 5cm dominos and place them in order it would take a certain time, and a certain amount of dominos to cover an area. It would also take some time between the time the first and the last domino fall.

Now imagine the same are covered with taller, 1 meter dominos. It is harder to make then yes, but you need less of them. Also, you have less dominos hitting one another and this leads to the overall time decreasing, but not necessarily.

There is a limit, a sweet spot, between size and speed where both can be maximized. The same thing happens in neurons but instead of dominos, there are myelin blocks, and instead of domino "hits" there are nodes of Ranvier.

There are other far more important bottlenecks to be concerned with.

Only now that we have a basic understand of how signals are propagated, can we see of the real bottlenecks. If you looks closer at the physiology, the really are two places where bottlenecks can be spotted: tramission in the neuron (between the nodes of Ranvier) and between neurons.

For transmission in the neuron, all that matters is ion channels. The problem is they take time to reset after being excited. Its the same thing as pressing a button. After you press it, you need wait for the button to go up to press it again.

For transmission between neurons, its all about neurotransmitters and receptors. This is a fancy way of saying how many messengers are available to deliver the signals (neurotransmitters) and how many mailboxes there are (receptors). There are several problems; the neurotransmitters can be used up quickly, there can be too few receptors or the receptors can become desensitized (don't respond as well to the signals that reach them as they should).

You have a lot of things to toy with if you focus on the two fields above. I can absolutely picture a drug that targets the receptors and makes them respond more lively to the signals as a solution to your problem.