There’s an old saying in neuroscience: neurons that fire together wire together. This means the more you run a neuro-circuit in your brain, the stronger that circuit becomes. This is why, to quote another old saw, practice makes perfect. The more you practice piano, or speaking a language, or juggling, the stronger those circuits get.
For years this has been the focus for learning new things. But as it turns out, the ability to learn is about more than building and strengthening neural connections. Even more important is our ability to break down the old ones. It’s called “synaptic pruning.” Here’s how it works.
YOUR BRAIN IS LIKE A GARDEN
Imagine your brain is a garden, except instead of growing flowers, fruits, and vegetables, you grow synaptic connections between neurons. These are the connections that neurotransmitters like dopamine, seratonin, and others travel across.
“Glial cells” are the gardeners of your brain–they act to speed up signals between certain neurons. But other glial cells are the waste removers, pulling up weeds, killing pests, raking up dead leaves. Your brain’s pruning gardeners are called “microglial cells.” They prune your synaptic connections. The question is, how do they know which ones to prune?
