How it fits together · lesson 2 of 10
How the brain rewires
Use it or lose it: how learning physically reshapes neural connections.
6 min read · reviewed October 2026
Strengthen what you use
Every time you learn or practice something, the connections (synapses) between neurons strengthen; connections you stop using weaken and get pruned. This 'use it or lose it' principle is the engine of all learning — and the reason novelty and challenge matter for keeping a sharp brain.
LTP, pruning, and myelination
Practice physically strengthens the brain circuits you use and prunes the ones you don't — which is why repetition builds skill and why challenging your brain keeps it sharp.
How it works →
Repeated activation drives long-term potentiation (LTP) — synapses that fire together strengthen — while unused connections are pruned. Learning also promotes myelination (faster signaling) and, in the hippocampus, the survival of new neurons. Novelty and effortful challenge drive these changes more than passive exposure.
What the studies show →
Classic studies (e.g. London taxi drivers' enlarged posterior hippocampi) and a large body of skill-acquisition research show structural brain changes from sustained, effortful practice.
Novelty and effort are the triggers
Comfortable, automatic activity doesn't reshape much. Learning something new and genuinely challenging — a language, an instrument, a skill — is what drives plasticity.
What best drives the brain to rewire and grow?
- Passive entertainment
- Novel, effortful challenge and practice
- Doing only what's already easy
- Avoiding mental effort to 'rest' the brain
Show the answer →
B.Novel, effortful challenge and practice
Plasticity is driven by novelty and effortful challenge — learning new, demanding skills. Comfortable, automatic activity does little to reshape the brain.