Last week we looked at several studies that demonstrated evidence of neuroplasticity in athletes’ brains–and saw that the brain physically changes and even grows with training and expertise. Brains, however, don’t exactly work like muscles, which keep growing and growing as they get stronger. After all, the skull is a fairly constrictive space, so growth in the cortex obviously has to stop at some point.
A new Scientific American article does a good job of discussing new findings around this more nuanced way that the brain grows changes. The basic overview is that acquiring a new skill leads to an initial burst of increased size in associated brain areas, but that the growth is at least partially reversed over time, as the brain prunes unnecessary connections and rewires itself more efficiently. So while the brain of a true expert may only be slightly larger in certain areas, brain regions associated with that expertise have gone through an extensive process of trial, error, revision and reinforcement to find the best neural pathways for executing a skill:
Studying the auditory cortex of rats, they found that the expansion of a ‘skill-specific’ brain area with training is only short lived, even when changes in ability are long lasting. Instead of working like a muscle, where training adds size and size begets prowess, learning seems to involve some heavy duty trimming as well. In fact, if Kilgard’s theory of learning holds up, both the biology of learning and our experience of it share a common principle: skill must be culled from a string of mistakes. Lots of them….
So what does change? Although newly learned perceptual skills don’t show up in a bird’s eye view of the cortex, they must have some neurobiological basis. Kilgard suggests that learning probably results from a few parsimonious tweaks at a more microscopic level, involving relatively small numbers of neurons and synapses….
It might be because your brain is no smarter than you are. Just as you don’t know how to move from novice to expert in a few optimal and wisely chosen moves (how could you?), your brain doesn’t either. In a provocative theory that describes his findings, Kilgard speculates that the expanding cortical map is like a search committee. It’s generating a huge range of candidate solutions to a problem the brain has been tasked with, but doesn’t yet know how to solve. (How do I discriminate these tones? How do I get the ball in the basket? How do I solve that tricky calculus problem?) Once a good solution is found, the search committee is disbanded. Efficient changes that impart skill are retained, and the non-meaningful changes are winnowed away as the map shrinks.
So the brain doesn’t quite work just like a muscle, although this process of pruning and reorganization may be more similar than it seems on its face. Parallels might be drawn between what we often call “functional strength” vs. brute, raw strength. Who knows exactly what Manny Pacquiao bench presses, but his functional strength when throwing a punch is probably a lot greater than a lot of people who have bigger muscles and can push more weight.
But of course it is ultimately the brain that controls the muscles, and here we might speculate about the connection between the two. Just like brain tissue doesn’t need to keep growing to accommodate expertise, if Manny Pacquiao has developed ultra-efficient neural pathways for the muscle activation, body control and balance required for punch-throwing, he maybe needs less pure muscle tissue to get the same bang for his buck.