The velocity at which an electrical signal propagates down an axon is determined, in part, by the thickness of the axon. Then we can expect that after holding all other factors equal, people with thicker axons process information faster. It wouldn't surprise me if there was significant variation in this trait, since the lower caloric expenditure associated with thinner axons and slower propagation of electrical signals could be helpful in environments where food is scarce, or where gestation and maturation needs to occur quickly. I can go to the gym to increase the size of my muscles, so is there any way to increase the thickness of my axons?

10 hours ago, Daniel Waxman said:

The velocity at which an electrical signal propagates down an axon is determined, in part, by the thickness of the axon. Then we can expect that after holding all other factors equal, people with thicker axons process information faster. It wouldn't surprise me if there was significant variation in this trait, since the lower caloric expenditure associated with thinner axons and slower propagation of electrical signals could be helpful in environments where food is scarce, or where gestation and maturation needs to occur quickly. I can go to the gym to increase the size of my muscles, so is there any way to increase the thickness of my axons?

Not that I'm personally aware of, but you might look into myelin sheathing given your interest in this topic

Trying to extrapolate effects in biology are often difficult- there is little evidence that action potential velocity leads to better processing. There are a lot of constraints (including energetic ones) and I think the physiological consequences are unclear. That being said, axon diameter actually do show some dynamics. Neurofilaments regulate axon dimensions and swelling has been observed during action potential generation as well as via mechanical tension of the cytoskeleton. Intuitively it makes sense to increase action potential velocity in connections that are heavily used rather than broad range increase which might mess up timing and activity coordination.

 

6 hours ago, CharonY said:

swelling has been observed during action potential generation as well as via mechanical tension of the cytoskeleton

To cause that swelling do you know if there are any specific chemicals used as energy sources for the mechanical tension, or for signaling it, or produced as waste products?