I work with a quadriplegic whose spinal nerves were almost but not quite severed, so he’s been doing pretty intensive physical therapy to restore his ability to walk, move his fingers, arms, etc. Yesterday, he had a big family Christmas dinner, and at night he was able to wiggle the fingers on his stubborn left hand for the first time. That got me thinking about the dopamine connection. I have about five minutes, so I’m just going to share some of the sources of inspiration as quickly as possible.
Axons run on the cause-effect principle, and dopamine is the reward chemical. Necessary for Pavlovian conditioning, etc. Axons can be strengthened (and I think the action potential is lowered?) by consistent, repetitive firing. This is certainly true in what we call “muscle memory”. People with chronic dopamine shortages display clumsiness, like in Parkinson’s and many people with Asperger’s, depression, et al. They observably lack muscle memory (and memory suffers in general in the absence of dopamine). Maybe that’s because their axon connections don’t get stronger because they don’t get the message that “firing is good, because dopamine”. But this wasn’t due so much to the lack of good actions, as pathological lack of the chemical that tells the brain the good action was completed.
So maybe a dopamine-saturated brain would re-establish its axons more quickly. Maybe that explains the people who experience miracle-type recovery.