I will try Tom, my thoughts on this are always evolving...
Talk of chemical reactions and the effects on the brain's architecture are interesting . But I am no neurosurgeon ....I build boats . That hands on approach may be affecting my thinking too, I will gladly admit that . I often get lost internally ( the same effect , but different method of getting there , to how a good ride will sometimes be ) concentrating hard ( it is surprisingly easy to feck it up in both cases if you don,t ) , rubbing down a boat for hours.
A " zen " state maybe..?
A release of dopamine ,endorphins ? dunno?
I used to farm livestock, and one of the clues to a stressed animal was repetitive motions. Done unthinkingly to release those helping chemicals. I can almost time the release of them when rubbing down a boat ( the repetitive motion again ) , 10 mins odd, I KNOW it is coming , push through the sleepy chemical ( whatever that is called ) and at 20 mins come out the other side and feel great . My co-workers often have to tap me on the shoulder.." tea up "...Again similar to riding, where did that last 2/3 hrs go , I remember every detail , down to the colour of the last car I overtook..but seems timeless...?
I try to think about how riding affects me, and the mentioned authors reach me and show two different approaches to the thinking ( in the philosophical meaning of the word

) that , for me at least , help to explain the why better ..if not the how.
Sorry for the ramble.....it is 4.30 am ish , I just woke up.....the old brain chemicals must be outta whack
