How far can neuronal axons reach within the brain? For example, have there been found single neurons that stretch from the occipital lobe all the way to the prefrontal cortex? Or maybe from the rightmost edge of the right temporal lobe to the leftmost edge of the left temporal lobe?

 

I'm asking because I'm wonder if any arbitrary brain center can potentially stimulate (or inhibit) any other arbitrary brain center (by "arbitrary", I mean given that one doesn't know - not that everyone's brain is different).

According to my textbook (Physiology of Behaviour) the longest axon in the body goes from the base of the brain to the foot.

 

And I know that axons can extend from one region of the cortex across the corpus callosum to another region of the cortex, though usually it's to the same structural region (i.e., parietal lobe to parietal lobe).

 

But as far as I'm aware the length of an axon is restricted by its diameter and the size of the soma, so too many long axons within the brain would possibly be disadvantageous.

 

So yes, it's possible, but as far as I'm aware it's not common.