Dr. Ann McKee: Why Doesn't the Brain's Plasticity Protect Us from CTE?

A cut heals. You can cope well without an appendix. But the brain's healing is limited. Each person has a limited number of neurons and Dr. Ann McKee talks about what it means when you lose them to a brain injury.

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How come when we cut ourselves it heals, you can’t even see where the cut was? If we injure our knee, our knee gradually recovers. We can have appendicitis that recovers. Why doesn’t the brain if it’s injured or if it has a stroke, why doesn’t it recover? And the main reason is that we’re born with a certain finite number of nerve cells, the neurons – it’s about three million, a trillion, that’s what people talk about. And those are the ones you get. You get one brain and one set of neurons. And they don’t replicate. I mean maybe they do a little bit in some very isolated parts of the brain, but it’s never a robust replication, so when you damage those neurons, they’re dead, they’re gone forever. You get scar formation, but you don’t get new neurons developing. So, the deficits that you experience because you’ve lost the neurons in that part of your brain, that’s not gonna get better. You can develop more circuits, more complicated circuits to circumvent the injury, and overcome the injury, but it’s not gonna be repairing that actual damage. And so that’s why the nervous system is so complicated. We only get one set of neurons, and we only have one brain, and it can’t duplicate itself, so repair is much more difficult in the nervous system. This video was produced by BrainLine thanks to generous support from the Infinite Hero Foundation.
Posted on BrainLine December 20, 2018.

About the author: Ann McKee, MD

Ann McKee, MD is the chief neuropathologist for the Framingham Heart Study and the Boston University-based Centenarian Study. She is also the chief neuropathologist for the Boston-based Veterans Administration Medical Centers and for the Sports Legacy Institute.

Ann McKee

This video was produced by BrainLine thanks to generous support from the Infinite Hero Foundation.